diff --git a/front/src/modules/simulationResult/components/SpaceTimeChartWrapper/helpers/configureHandlePan.ts b/front/src/modules/simulationResult/components/SpaceTimeChartWrapper/helpers/configureHandlePan.ts
index 31f1f31edea..2496b522728 100644
--- a/front/src/modules/simulationResult/components/SpaceTimeChartWrapper/helpers/configureHandlePan.ts
+++ b/front/src/modules/simulationResult/components/SpaceTimeChartWrapper/helpers/configureHandlePan.ts
@@ -5,6 +5,7 @@ import {
   type SpaceTimeChartProps,
 } from '@osrd-project/ui-charts';
 
+import { isExceptionStartTimeException } from 'modules/trainSchedule/helpers/pacedTrain';
 import type { TrainId } from 'reducers/osrdconf/types';
 import { updateSelectedTrain } from 'reducers/simulationResults';
 import type { AppDispatch } from 'store';
@@ -84,7 +85,7 @@ export function configureHandlePan({
       // if the dragged train is an occurrence, we need to update the first occurrence because the others are based on it
       if (
         isIndividualOccurrenceProjection(draggedTrain) &&
-        (!draggedTrain.exception || !draggedTrain.exception.start_time)
+        !isExceptionStartTimeException(draggedTrain.exception)
       ) {
         const occurrencesIndex = extractOccurrenceIndexFromOccurrenceId(draggedTrain.id);
         const pacedTrainId = extractEditoastIdFromPacedTrainId(
@@ -134,9 +135,8 @@ export function configureHandlePan({
       }
 
       // disable start time exception for now
-      const isStartTimeException =
-        isIndividualOccurrenceProjection(train) && !!train.exception?.start_time;
-      if (isStartTimeException) return;
+      if (isIndividualOccurrenceProjection(train) && isExceptionStartTimeException(train.exception))
+        return;
 
       setDraggingState({
         draggedTrain: train,
diff --git a/front/src/modules/trainSchedule/helpers/pacedTrain.ts b/front/src/modules/trainSchedule/helpers/pacedTrain.ts
index c033cc9e5d2..054c1777d55 100644
--- a/front/src/modules/trainSchedule/helpers/pacedTrain.ts
+++ b/front/src/modules/trainSchedule/helpers/pacedTrain.ts
@@ -224,6 +224,20 @@ export const getOccurrenceTrainName = (
   return `${pacedTrain.train_name}/+`;
 };
 
+export const isExceptionStartTimeException = (
+  exception: PacedTrainException | undefined
+): boolean => exception?.start_time !== undefined;
+
+/**
+ * Returns true if the occurrence identified by occurrenceId is a startTime exception.
+ * Returns false for occurrences with no exception at all (they are startTime-compliant).
+ */
+export const isOccurrenceStartTimeException = (
+  occurrenceId: OccurrenceId,
+  exceptions: PacedTrainException[]
+): boolean =>
+  isExceptionStartTimeException(findExceptionWithOccurrenceId(exceptions, occurrenceId));
+
 /**
  * Return true if the exception has at least one change group defined (excluding disabled).
  */