Use consistent beginning_of_day function

openedx/core/djangoapps/schedules/tasks.py

@@ -65,7 +65,7 @@ class ScheduleMessageBaseTask(Task):
 
     @classmethod
     def enqueue(cls, site, current_date, day_offset, override_recipient_email=None):
-        current_date = current_date.replace(hour=0, minute=0, second=0)
+        current_date = resolvers._get_datetime_beginning_of_day(current_date)
 
         if not cls.is_enqueue_enabled(site):
             cls.log_debug(

openedx/core/djangoapps/schedules/tests/test_tasks.py

@@ -58,7 +58,7 @@ class TestScheduleMessageBaseTask(CacheIsolationTestCase):
                 current_date=current_date,
                 day_offset=day_offset
             )
-            target_date = current_date.replace(hour=0, minute=0, second=0) + \
+            target_date = current_date.replace(hour=0, minute=0, second=0, microsecond=0) + \
                 datetime.timedelta(day_offset)
             print(patches['log_debug'].mock_calls)
             patches['log_debug'].assert_any_call(