Fix ContinuousTimetable false triggering when last run ends in future

airflow/timetables/simple.py

@@ -137,14 +137,21 @@ def next_dagrun_info(
     ) -> DagRunInfo | None:
         if restriction.earliest is None:  # No start date, won't run.
             return None
+
+        current_time = timezone.coerce_datetime(timezone.utcnow())
+
         if last_automated_data_interval is not None:  # has already run once
-            start = last_automated_data_interval.end
-            end = timezone.coerce_datetime(timezone.utcnow())
+            if last_automated_data_interval.end > current_time:  # start date is future
+                start = restriction.earliest
+                elapsed = last_automated_data_interval.end - last_automated_data_interval.start
+
+                end = start + elapsed.as_timedelta()
+            else:
+                start = last_automated_data_interval.end
+                end = current_time
         else:  # first run
             start = restriction.earliest
-            end = max(
-                restriction.earliest, timezone.coerce_datetime(timezone.utcnow())
-            )  # won't run any earlier than start_date
+            end = max(restriction.earliest, current_time)
 
         if restriction.latest is not None and end > restriction.latest:
             return None

tests/timetables/test_continuous_timetable.py

@@ -89,3 +89,14 @@ def test_no_runs_after_end_date(timetable, restriction):
     )
 
     assert next_info is None
+
+
+@time_machine.travel(BEFORE_DATE)
+def test_no_false_triggering_with_future_start_date_after_run(timetable, restriction):
+    next_info = timetable.next_dagrun_info(
+        last_automated_data_interval=DataInterval(BEFORE_DATE, BEFORE_DATE.add(hours=1)),
+        restriction=restriction,
+    )
+
+    assert next_info is not None
+    assert next_info.data_interval.start == START_DATE