diff --git a/backend/tests/test_reminder_scheduler.py b/backend/tests/test_reminder_scheduler.py
index ea976cb..a7bcc26 100644
--- a/backend/tests/test_reminder_scheduler.py
+++ b/backend/tests/test_reminder_scheduler.py
@@ -66,3 +66,60 @@ async def test_enqueue_due_reminders_dedupes_jobs(app_module, mocker):
     assert first["queued"] == 1
     assert second["queued"] == 0
     task.assert_called_once_with("due-user")
+
+@pytest.mark.asyncio
+async def test_enqueue_due_reminders_allows_new_reminder_windows(app_module, mocker):
+    from alerts import progress_checker
+
+    app_module.db.preferences.records.append(
+        {
+            "user_id": "due-user",
+            "is_opted_in": True,
+            "timezone": "Asia/Kolkata",
+            "whatsapp_number": "+911234567890",
+        }
+    )
+    progress_checker.db = app_module.db
+
+    task = mocker.patch(
+        "tasks.reminder_tasks.check_user_progress_and_alert_task.delay",
+        autospec=True,
+    )
+
+    first_window = datetime(2026, 1, 1, 17, 30, tzinfo=timezone.utc)
+    second_window = datetime(2026, 1, 2, 17, 30, tzinfo=timezone.utc)
+
+    first = await progress_checker.enqueue_due_reminders(first_window)
+    second = await progress_checker.enqueue_due_reminders(second_window)
+
+    assert first["queued"] == 1
+    assert second["queued"] == 1
+    assert task.call_count == 2
+@pytest.mark.asyncio
+async def test_enqueue_due_reminders_deduplication_is_window_specific(
+    app_module, mocker
+):
+    from alerts import progress_checker
+
+    app_module.db.preferences.records.append(
+        {
+            "user_id": "due-user",
+            "is_opted_in": True,
+            "timezone": "Asia/Kolkata",
+            "whatsapp_number": "+911234567890",
+        }
+    )
+    progress_checker.db = app_module.db
+
+    task = mocker.patch(
+        "tasks.reminder_tasks.check_user_progress_and_alert_task.delay",
+        autospec=True,
+    )
+
+    window_one = datetime(2026, 1, 1, 17, 30, tzinfo=timezone.utc)
+    window_two = datetime(2026, 1, 1, 18, 30, tzinfo=timezone.utc)
+
+    await progress_checker.enqueue_due_reminders(window_one)
+    await progress_checker.enqueue_due_reminders(window_two)
+
+    assert task.call_count == 2