diff --git a/android/app/src/main/kotlin/es/freetimelab/pluriwave/AlarmScheduler.kt b/android/app/src/main/kotlin/es/freetimelab/pluriwave/AlarmScheduler.kt
index e260f86..e19210f 100644
--- a/android/app/src/main/kotlin/es/freetimelab/pluriwave/AlarmScheduler.kt
+++ b/android/app/src/main/kotlin/es/freetimelab/pluriwave/AlarmScheduler.kt
@@ -717,7 +717,12 @@ class AlarmScheduler(private val context: Context) {
         val now = System.currentTimeMillis()
         spec.snoozeUntilMillis?.let { if (it > now) return it }
         if (!spec.enabled) return null
-        val base = maxOf(now, (spec.lastHandledAtMillis ?: 0L) + 60_000L)
+        // handledFloor is a HARD lower bound: an occurrence already fired
+        // (onAlarmFired records lastHandledAtMillis) can never be re-selected,
+        // so the grace window below can lower `base` toward the past without
+        // ever risking a double-fire.
+        val handledFloor = (spec.lastHandledAtMillis ?: 0L) + 60_000L
+        val base = maxOf(now - IMMINENT_TOLERANCE_MILLIS, handledFloor)
         return when (spec.scheduleType) {
             SCHEDULE_UNICA -> computeOneShot(spec, base)
             SCHEDULE_DIAS_SEMANA -> computeWeekday(spec, base)
@@ -1042,6 +1047,15 @@ class AlarmScheduler(private val context: Context) {
         private const val PRE_NOTICE_MILLIS = 30 * 60 * 1000L
         private const val SCHEDULE_UNICA = "unica"
         private const val SCHEDULE_DIAS_SEMANA = "diasSemana"
+
+        // Mirror Dart's ServicioProgramacionAlarmas.toleranciaDisparoInminente
+        // (90s): an occurrence whose trigger just passed within this window
+        // must still be armed (and delivered ~immediately) instead of being
+        // skipped to the next day. Without it, a re-arm landing microseconds
+        // after the trigger (e.g. the periodic resync straddling the trigger
+        // instant while the app is foregrounded) recomputes the next
+        // occurrence as tomorrow and cancels the in-flight fire.
+        private const val IMMINENT_TOLERANCE_MILLIS = 90_000L
     }
 }
 
diff --git a/test/servicios/servicio_programacion_alarmas_test.dart b/test/servicios/servicio_programacion_alarmas_test.dart
index a6d2aae..7590270 100644
--- a/test/servicios/servicio_programacion_alarmas_test.dart
+++ b/test/servicios/servicio_programacion_alarmas_test.dart
@@ -167,6 +167,50 @@ void main() {
       expect(proxima, DateTime(2026, 5, 26, 7, 30));
     });
 
+    test('mantiene la ocurrencia diaria cuyo disparo acaba de pasar', () {
+      // Contract the native AlarmScheduler.computeNextTriggerMillis MUST
+      // mirror: a trigger that just passed within toleranciaDisparoInminente
+      // (90s) and has NOT been handled is kept (normalized to desde + 2s),
+      // never skipped to tomorrow. The native side lacking this window is
+      // what recomputed the next occurrence as tomorrow and cancelled the
+      // in-flight fire, so the alarm never rang until the screen was turned
+      // on. If this expectation changes, the native constant
+      // IMMINENT_TOLERANCE_MILLIS must change with it.
+      final alarma = AlarmaMusical(
+        id: 'a-inminente-diaria',
+        nombre: 'Diaria inminente',
+        hora: 22,
+        minuto: 35,
+        tipoProgramacion: TipoProgramacionAlarma.diaria,
+        diasSemana: const [],
+      );
+
+      final proxima = servicio.calcularProxima(
+        alarma: alarma,
+        desde: DateTime(2026, 7, 11, 22, 35, 30),
+      );
+
+      expect(proxima, DateTime(2026, 7, 11, 22, 35, 32));
+    });
+
+    test('mantiene la ocurrencia por dias de semana recien pasada', () {
+      final alarma = AlarmaMusical(
+        id: 'a-inminente-semana',
+        nombre: 'Semana inminente',
+        hora: 22,
+        minuto: 35,
+        tipoProgramacion: TipoProgramacionAlarma.diasSemana,
+        diasSemana: const [1, 2, 3, 4, 5, 6, 7],
+      );
+
+      final proxima = servicio.calcularProxima(
+        alarma: alarma,
+        desde: DateTime(2026, 7, 11, 22, 35, 30),
+      );
+
+      expect(proxima, DateTime(2026, 7, 11, 22, 35, 32));
+    });
+
     test('calcula siguiente por dias de semana despues de ejecucion', () {
       final alarma = AlarmaMusical(
         id: 'a7',