diff --git a/entry/src/main/ets/common/CalendarDataService.ets b/entry/src/main/ets/common/CalendarDataService.ets
index d749055..e693588 100644
--- a/entry/src/main/ets/common/CalendarDataService.ets
+++ b/entry/src/main/ets/common/CalendarDataService.ets
@@ -153,11 +153,14 @@ export class CalendarDataService {
           rows.push(m);
         }
       }
-      // 单次覆盖实例（RECURRENCE-ID 独立行）：展开时跳过对应发生，避免重复
+      // 单次覆盖实例（RECURRENCE-ID 独立行）：展开时跳过对应发生，避免重复。
+      // 注意：①排除键必须带 calKey（同一系列可能出现在多个日历本）；
+      // ②只有"可见日历本"的覆盖行才参与排除——历史孤儿行（旧账号迁移残留）
+      //    自己不显示，却会把主事件的对应发生排除掉，导致"第一次不显示"
       const overrideKeys: string[] = [];
       for (const e of rows) {
-        if (e.rrule === '' && e.recurring) {
-          overrideKeys.push(`${e.uid}_${e.startTime}`);
+        if (e.rrule === '' && e.recurring && visibleKeys.includes(e.calKey)) {
+          overrideKeys.push(`${e.calKey}_${e.uid}_${e.startTime}`);
         }
       }
       let occTotal: number = 0;
@@ -181,7 +184,8 @@ export class CalendarDataService {
           }
           const occs: number[] = RruleUtil.expand(e.rrule, e.startTime, start, end, exNums, 1500);
           if (occs.length > 0) {
-            times = occs.filter((occ: number): boolean => !overrideKeys.includes(`${e.uid}_${occ}`));
+            times = occs.filter((occ: number): boolean =>
+              !overrideKeys.includes(`${e.calKey}_${e.uid}_${occ}`));
           }
         }
         for (const occ of times) {
diff --git a/entry/src/main/ets/common/CardDataService.ets b/entry/src/main/ets/common/CardDataService.ets
index 0b2f2f7..bf634dd 100644
--- a/entry/src/main/ets/common/CardDataService.ets
+++ b/entry/src/main/ets/common/CardDataService.ets
@@ -121,13 +121,15 @@ export class CardDataService {
       const end: number = start + 60 * 86400000;
       const sources = await CalendarDataService.loadSources(context);
       const events: DisplayEvent[] = await CalendarDataService.loadEvents(context, start, end, sources);
-      // 1) 过滤已结束超过 1 小时的；2) 按天分组，组内全天在前、有时间按开始时间排序；
+      // 1) 过滤：保留"今天 0 点以来"的日程（今天已结束的也显示，否则重复日程的
+      //    第一次发生会被隐藏，表现为"第一次不显示、第二次及以后显示"）；
+      // 2) 按天分组，组内全天在前、有时间按开始时间排序；
       // 3) 平铺输出并给每组第一条打 showDate 标记（日期头只跟在自己日期前面）
       // 跨天日程：已开始未结束的归到"今天"、按全天显示，不再从开始那天重复显示
-      const upcoming: DisplayEvent[] = events
-        .filter((e: DisplayEvent): boolean => e.endTime >= now.getTime() - 3600000);
-
       const todayKey: number = CardDataService.startOfDay(now.getTime());
+      const upcoming: DisplayEvent[] = events
+        .filter((e: DisplayEvent): boolean => e.endTime >= todayKey);
+
       const dayKey = (ms: number): number => CardDataService.startOfDay(ms);
       const spansDays = (e: DisplayEvent): boolean =>
         dayKey(e.endTime) > dayKey(e.startTime);
diff --git a/entry/src/main/ets/common/EventDb.ets b/entry/src/main/ets/common/EventDb.ets
index cc4a78e..1c8fed4 100644
--- a/entry/src/main/ets/common/EventDb.ets
+++ b/entry/src/main/ets/common/EventDb.ets
@@ -368,8 +368,8 @@ export class EventDb {
         await store.insert('events', EventDb.toBucket(e));
         added++;
       } else if (found.etag !== r.etag || found.rrule !== r.rrule || found.exdate !== r.exdate
-        || found.reminder !== r.reminder) {
-        // 更新（rrule/exdate 变化也更新，兼容老数据回填）
+        || found.reminder !== r.reminder || found.recurring !== r.recurring) {
+        // 更新（rrule/exdate/recurring 变化也更新，兼容老数据回填）
         found.title = r.title;
         found.description = r.description;
         found.location = r.location;
@@ -417,6 +417,26 @@ export class EventDb {
     await store.delete(predicates);
   }
 
+  /**
+   * 清理孤儿行：calKey 既不是本机日历（local）、也不属于任何现有账号（accId_ 前缀）的历史残留数据。
+   * 典型来源：账号删除重建、日历重选后序号变化遗留的旧 calKey（如 `_13`、`acc1789274273124_0_13`）。
+   * 这些行会参与重复日程的 override 排除计算，导致重复日程的第一次发生不显示，必须物理删除。
+   * 匹配规则为前缀包含（NOT LIKE 'accId_%' 的 AND 组合），宁可少删不会误删有效数据。
+   */
+  static async pruneOrphanCalKeys(context: common.Context, accIds: string[]): Promise<number> {
+    const store = await EventDb.getDb(context);
+    const predicates = new relationalStore.RdbPredicates('events');
+    predicates.notEqualTo('cal_key', 'local');
+    for (const id of accIds) {
+      if (id === '') {
+        continue;
+      }
+      predicates.and().notLike('cal_key', `${id}_%`);
+    }
+    const removed: number = await store.delete(predicates);
+    return removed;
+  }
+
   /**
    * 重新勾选日历本后清理失效数据：
    * 删除该账号下 calKey 不在有效列表中的本地日程/待办（calKey = accId_序号，重选后序号会变）
diff --git a/entry/src/main/ets/common/IcsUtil.ets b/entry/src/main/ets/common/IcsUtil.ets
index 428bc45..5a91028 100644
--- a/entry/src/main/ets/common/IcsUtil.ets
+++ b/entry/src/main/ets/common/IcsUtil.ets
@@ -91,7 +91,7 @@ export class IcsUtil {
         current.description = IcsUtil.unescape(value);
       } else if (propName === 'LOCATION') {
         current.location = IcsUtil.unescape(value);
-      } else if (propName === 'RRULE' || propName === 'RECURREIENCE-ID') {
+      } else if (propName === 'RRULE' || propName === 'RECURRENCE-ID') {
         current.recurring = true;
         if (propName === 'RRULE') {
           current.rrule = value;
diff --git a/entry/src/main/ets/common/RruleUtil.ets b/entry/src/main/ets/common/RruleUtil.ets
index 877d23c..7a8d59c 100644
--- a/entry/src/main/ets/common/RruleUtil.ets
+++ b/entry/src/main/ets/common/RruleUtil.ets
@@ -108,6 +108,13 @@ export class RruleUtil {
       if (targets.length === 0) {
         targets.push(base.getDay());
       }
+      // RFC 5545：DTSTART 始终是第一次发生——即使它的星期不在 BYDAY 中
+      // （例如周二创建的"每周一重复"日程，第一次是周二那次，必须显示）
+      if (byday.length > 0 && !targets.includes(base.getDay())) {
+        if (!accept(dtstart)) {
+          return result;
+        }
+      }
       const anchorWeek: number = RruleUtil.weekStartMs(dtstart);
       let dayMs: number = baseZeroMs;
       let guard: number = 0;
@@ -129,6 +136,13 @@ export class RruleUtil {
       let y: number = base.getFullYear();
       let m: number = base.getMonth();
       let guard: number = 0;
+      // RFC 5545：DTSTART 始终是第一次发生——即使它的日期不在 BYMONTHDAY 中
+      if (bymonthday.length > 0 &&
+        !bymonthday.some((v: number): boolean => v === base.getDate())) {
+        if (!accept(dtstart)) {
+          return result;
+        }
+      }
       while (guard < 1500) {
         guard++;
         const monthFirst: number = new Date(y, m, 1).getTime();
diff --git a/entry/src/main/ets/common/SyncEngine.ets b/entry/src/main/ets/common/SyncEngine.ets
index 0b4f8ec..72d3798 100644
--- a/entry/src/main/ets/common/SyncEngine.ets
+++ b/entry/src/main/ets/common/SyncEngine.ets
@@ -201,4 +201,23 @@ export class SyncEngine {
       }
     }
   }
+
+  /**
+   * 清理孤儿日程行：calKey 不属于任何现有账号（accId_ 前缀）也不是本机日历（local）的历史残留。
+   * 典型如账号重建/日历重选后遗留的 `_13`、`acc1789274273124_0_13` 等，
+   * 这些行会参与重复日程的 override 排除计算，导致重复日程第一次发生不显示。
+   * 建议在所有账号同步完成后调用。
+   */
+  static async pruneOrphanRows(context: common.Context, accounts: DavAccount[]): Promise<void> {
+    try {
+      const accIds: string[] = accounts.map((a: DavAccount): string => a.id);
+      const removed: number = await EventDb.pruneOrphanCalKeys(context, accIds);
+      if (removed > 0) {
+        LogUtil.write(`清理孤儿日程行：${removed} 条（calKey 不属于任何现有账号）`);
+      }
+    } catch (err) {
+      const e = err as BusinessError;
+      LogUtil.write(`清理孤儿日程行失败(忽略)：${e.message}`);
+    }
+  }
 }
\ No newline at end of file
diff --git a/entry/src/main/ets/pages/AccountsPage.ets b/entry/src/main/ets/pages/AccountsPage.ets
index 71fde35..b4e990b 100644
--- a/entry/src/main/ets/pages/AccountsPage.ets
+++ b/entry/src/main/ets/pages/AccountsPage.ets
@@ -76,6 +76,7 @@ struct AccountsPage {
       if (acc.type === TYPE_CALDAV) {
         await SyncEngine.withTimeout(
           SyncEngine.syncAccount(context as common.UIAbilityContext, acc), 120000);
+        await SyncEngine.pruneOrphanRows(context, this.accounts);
       }
       acc.itemCount = acc.calendarHrefs.length;
       acc.lastSyncTime = this.formatNow();
diff --git a/entry/src/main/ets/pages/Index.ets b/entry/src/main/ets/pages/Index.ets
index 58f1117..6a21400 100644
--- a/entry/src/main/ets/pages/Index.ets
+++ b/entry/src/main/ets/pages/Index.ets
@@ -3,7 +3,7 @@
 // 混合展示 DAV 与系统日历；每分钟自动同步；可"回到今天"
 import { router } from '@kit.ArkUI';
 import { common } from '@kit.AbilityKit';
-import { BusinessError } from '@kit.BasicServicesKit';
+import { BusinessError, pasteboard } from '@kit.BasicServicesKit';
 import { DavAccount, AccountStore, CalSource, TYPE_CALDAV } from '../common/AccountStore';
 import { DisplayEvent, CalendarDataService } from '../common/CalendarDataService';
 import { SyncEngine } from '../common/SyncEngine';
@@ -12,6 +12,9 @@ import { LunarUtil } from '../common/LunarUtil';
 import { CardDataService } from '../common/CardDataService';
 import { ReminderService } from '../common/ReminderService';
 import { AppSettings } from '../common/AppSettings';
+import { EventDb, LocalEvent } from '../common/EventDb';
+import { RruleUtil } from '../common/RruleUtil';
+import { IcsUtil } from '../common/IcsUtil';
 
 /** 月视图单元格 */
 class MonthCell {
@@ -284,6 +287,7 @@ struct Index {
       }
       await SyncEngine.withTimeout(
         SyncEngine.syncAccount(context as common.UIAbilityContext, acc), 120000);
+      await SyncEngine.pruneOrphanRows(context, this.accounts);
       acc.lastSyncTime = this.formatNow();
       await AccountStore.saveAll(context, this.accounts);
       this.getUIContext().getPromptAction()
@@ -341,6 +345,7 @@ struct Index {
     }
     try {
       await SyncEngine.settleLocalEvents(context);
+      await SyncEngine.pruneOrphanRows(context, this.accounts);
       await AccountStore.saveAll(context, this.accounts);
     } catch (err) {
       const e = err as BusinessError;
@@ -608,7 +613,7 @@ struct Index {
       })
   }
 
-  /** 切换视图：进入列表视图时按需加载（今天 ~ 未来2年，已结束的不显示） */
+  /** 切换视图：进入列表视图时按需加载（今天整天 ~ 未来2年，昨天之前已结束的不显示） */
   private async handleModeSwitch(key: string): Promise<void> {
     this.mode = key;
     if (key === 'agenda') {
@@ -630,8 +635,9 @@ struct Index {
     const end: number = now + 730 * 86400000;
     try {
       const raw: DisplayEvent[] = await CalendarDataService.loadEvents(context, start, end, this.sources);
-      // 只保留未结束的（跨天进行中的保留）；跨天且已开始的归到今天，与卡片一致
-      this.agendaEvents = raw.filter((e: DisplayEvent): boolean => e.endTime >= now - 3600000);
+      // 保留"今天 0 点以来"的全部日程：今天已结束的也显示（否则重复日程的第一次发生会被隐藏），
+      // 昨天及更早且已结束的不显示；跨天进行中的归到今天，与卡片一致
+      this.agendaEvents = raw.filter((e: DisplayEvent): boolean => e.endTime >= start);
       this.agendaGroupsData = this.buildAgendaGroups(this.agendaEvents);
       this.agendaStale = false;
       LogUtil.write(`列表视图加载：${this.agendaEvents.length} 条（今天~未来2年），分组 ${this.agendaGroupsData.length} 组`);
@@ -752,6 +758,9 @@ struct Index {
       }
       .width('100%')
       .padding({ left: 20, right: 20, top: 6 })
+      .gesture(LongPressGesture().onAction(() => {
+        this.showOccurrenceDebug(this.selectedDate);
+      }))
 
       this.eventList()
     }
@@ -759,6 +768,110 @@ struct Index {
     .layoutWeight(1)
   }
 
+  /** 调试（临时）：长按月视图日期标题，检查重复日程在该日的首次发生情况 */
+  private async showOccurrenceDebug(dateMs: number): Promise<void> {
+    const context = this.getUIContext().getHostContext();
+    if (context === undefined) {
+      return;
+    }
+    try {
+      const dayStart: number = this.startOfDay(dateMs);
+      const dayEnd: number = dayStart + 86400000;
+      const winStart: number = dayStart - 365 * 86400000;
+      const winEnd: number = dayEnd + 365 * 86400000;
+      const rows: LocalEvent[] = await EventDb.queryRange(context, winStart, winEnd);
+      const sources = await CalendarDataService.loadSources(context);
+      const visibleKeys: string[] = sources.filter((s: CalSource): boolean => s.visible)
+        .map((s: CalSource): string => s.calKey);
+      const masters = new Map<string, LocalEvent>();
+      const overrides = new Map<string, LocalEvent[]>();
+      for (const r of rows) {
+        if (r.rrule !== '') {
+          masters.set(r.uid, r);
+        } else {
+          const arr = overrides.get(r.uid);
+          if (arr === undefined) {
+            overrides.set(r.uid, [r]);
+          } else {
+            arr.push(r);
+          }
+        }
+      }
+      const p = (n: number): string => (n < 10 ? '0' + n : String(n));
+      const fmt = (ms: number): string => {
+        const d = new Date(ms);
+        return `${d.getFullYear()}-${p(d.getMonth() + 1)}-${p(d.getDate())} ${p(d.getHours())}:${p(d.getMinutes())}`;
+      };
+      const lines: string[] = [`调试 ${this.fmtDateCn(dateMs)}`, `visibleKeys=${visibleKeys.join(',')}`];
+      let idx: number = 0;
+      for (const m of masters.values()) {
+        if (idx >= 6) {
+          lines.push('…（更多系列省略）');
+          break;
+        }
+        // 只列出与该日期相关的系列：主行开始日在该日±90天内，或展开命中该日
+        const exNums: number[] = [];
+        if (m.exdate !== '') {
+          for (const raw of m.exdate.split(';')) {
+            const t = IcsUtil.parseTime(raw, !raw.includes('T'));
+            if (t !== null) {
+              exNums.push(t.time);
+            }
+          }
+        }
+        const occs: number[] = RruleUtil.expand(m.rrule, m.startTime, m.startTime, winEnd, exNums, 400);
+        const hitsDay: boolean = occs.some((o: number): boolean => o >= dayStart && o < dayEnd);
+        const nearStart: boolean = Math.abs(m.startTime - dayStart) <= 90 * 86400000;
+        if (!hitsDay && !nearStart) {
+          continue;
+        }
+        idx++;
+        const hasFirst: boolean = occs.some((o: number): boolean => o === m.startTime);
+        const mVis: boolean = visibleKeys.includes(m.calKey);
+        lines.push(`◇ ${m.title}`);
+        lines.push(`  uid=${m.uid.substring(0, 8)} 主行=${fmt(m.startTime)} rec=${m.recurring ? 1 : 0} calKey=${m.calKey} vis=${mVis ? 1 : 0} dirty=${m.dirty ? 1 : 0}`);
+        lines.push(`  rrule=${m.rrule === '' ? '(空!)' : m.rrule}`);
+        lines.push(`  exdate=${m.exdate === '' ? '无' : m.exdate}`);
+        lines.push(`  展开条数=${occs.length} 含首次=${hasFirst ? '是' : '否'} 首次=${occs.length > 0 ? fmt(occs[0]) : '无'} 该日发生=${hitsDay ? '是' : '否'}`);
+        const ovs = overrides.get(m.uid) ?? [];
+        if (ovs.length === 0) {
+          lines.push('  覆盖实例: 无');
+        } else {
+          for (const o of ovs.slice(0, 5)) {
+            const oVis: boolean = visibleKeys.includes(o.calKey);
+            lines.push(`  覆盖: ${fmt(o.startTime)}~${fmt(o.endTime)} rec=${o.recurring ? 1 : 0} calKey=${o.calKey} vis=${oVis ? 1 : 0} dirty=${o.dirty ? 1 : 0}`);
+          }
+          if (ovs.length > 5) {
+            lines.push(`  覆盖共 ${ovs.length} 条`);
+          }
+        }
+      }
+      if (lines.length <= 2) {
+        lines.push('（该日期附近没有重复主事件）');
+      }
+      const text: string = lines.join('\n').substring(0, 3500);
+      this.getUIContext().showAlertDialog({
+        title: '重复日程调试',
+        message: text,
+        autoCancel: true,
+        alignment: DialogAlignment.Center,
+        primaryButton: {
+          value: '复制',
+          action: (): void => {
+            const data = pasteboard.createData(pasteboard.MIMETYPE_TEXT_PLAIN, text);
+            pasteboard.getSystemPasteboard().setData(data);
+          }
+        },
+        secondaryButton: {
+          value: '关闭',
+          action: (): void => {}
+        }
+      });
+    } catch (err) {
+      // 调试失败不影响主流程
+    }
+  }
+
   /** 周视图整周切换（左滑下一周、右滑上一周）；跨月时自动重载数据 */
   private switchWeek(delta: number): void {
     this.selectedDate += delta * 7 * 86400000;
diff --git a/entry/src/main/ets/syncwork/SyncWorkAbility.ets b/entry/src/main/ets/syncwork/SyncWorkAbility.ets
index 8641e64..526f3ec 100644
--- a/entry/src/main/ets/syncwork/SyncWorkAbility.ets
+++ b/entry/src/main/ets/syncwork/SyncWorkAbility.ets
@@ -39,6 +39,7 @@ export default class SyncWorkAbility extends WorkSchedulerExtensionAbility {
         }
       }
       await SyncEngine.settleLocalEvents(context);
+      await SyncEngine.pruneOrphanRows(context, accounts);
       // 同步后刷新卡片 + 重建提醒，保证后台同步的成果直接可见
       await CardDataService.pushToAllForms(context);
       await ReminderService.refreshReminders(context);