diff --git a/apps/api/tests/broker/reminderScheduler.test.ts b/apps/api/tests/broker/reminderScheduler.test.ts
index 293f6ec..b86946d 100644
--- a/apps/api/tests/broker/reminderScheduler.test.ts
+++ b/apps/api/tests/broker/reminderScheduler.test.ts
@@ -659,8 +659,13 @@ describe('reminderScheduler — NOTIF-06: all-day 9 AM-local fire branch', () =>
   // All-day tests use the server timezone (America/New_York = UTC-4 in summer).
   // computeAlertInstantUtc('2026-06-15', 0, 'America/New_York') = 2026-06-15T13:00:00Z.
   // Tests set `now` to the expected alert UTC to trigger the fire window.
+  // Pin TZ explicitly so these assertions are deterministic regardless of the host/CI
+  // timezone (CI runs UTC; the scheduler reads process.env.TZ at call time, D-04).
+  let prevTz: string | undefined;
 
   beforeEach(() => {
+    prevTz = process.env.TZ;
+    process.env.TZ = 'America/New_York';
     vi.useFakeTimers();
     vi.resetModules();
   });
@@ -668,6 +673,8 @@ describe('reminderScheduler — NOTIF-06: all-day 9 AM-local fire branch', () =>
   afterEach(() => {
     vi.useRealTimers();
     vi.clearAllMocks();
+    if (prevTz === undefined) delete process.env.TZ;
+    else process.env.TZ = prevTz;
   });
 
   it('all-day 0-lead fires at 9 AM local (not midnight) on event date', async () => {
diff --git a/apps/pwa/src/components/EventForm.test.tsx b/apps/pwa/src/components/EventForm.test.tsx
index 87e4290..b7ee23f 100644
--- a/apps/pwa/src/components/EventForm.test.tsx
+++ b/apps/pwa/src/components/EventForm.test.tsx
@@ -1246,7 +1246,7 @@ describe('EventForm — Phase 11 reminder picker (Plan 04)', () => {
  * This field is added by Plan 05 — before the fix, CalendarOccurrence does not carry it,
  * so the form cannot distinguish custom from no-reminder.
  */
-const CUSTOM_ALARM_OCCURRENCE: CalendarOccurrence & { reminderIsCustom?: boolean } = {
+const CUSTOM_ALARM_OCCURRENCE: CalendarOccurrence = {
   id: 'custom-alarm-uid::2026-12-15',
   uid: 'custom-alarm-uid',
   calendarId: 1,
@@ -1280,7 +1280,7 @@ describe('EventForm — Phase 11 Plan 05 CR-01: custom alarm round-trip', () =>
     renderForm({
       mode: 'edit',
       uid: 'custom-alarm-uid',
-      eventOccurrence: CUSTOM_ALARM_OCCURRENCE as CalendarOccurrence,
+      eventOccurrence: CUSTOM_ALARM_OCCURRENCE,
     });
 
     const reminderSelect = document.querySelector('#event-reminder') as HTMLSelectElement;
@@ -1293,7 +1293,7 @@ describe('EventForm — Phase 11 Plan 05 CR-01: custom alarm round-trip', () =>
     renderForm({
       mode: 'edit',
       uid: 'custom-alarm-uid',
-      eventOccurrence: CUSTOM_ALARM_OCCURRENCE as CalendarOccurrence,
+      eventOccurrence: CUSTOM_ALARM_OCCURRENCE,
     });
 
     // The read-only "Custom (kept)" option must be visible
@@ -1307,7 +1307,7 @@ describe('EventForm — Phase 11 Plan 05 CR-01: custom alarm round-trip', () =>
     renderForm({
       mode: 'edit',
       uid: 'custom-alarm-uid',
-      eventOccurrence: CUSTOM_ALARM_OCCURRENCE as CalendarOccurrence,
+      eventOccurrence: CUSTOM_ALARM_OCCURRENCE,
     });
 
     // Change the title to simulate a real edit