diff --git a/app/Http/Controllers/VolunteerController.php b/app/Http/Controllers/VolunteerController.php
index 9b49b49..23083b4 100644
--- a/app/Http/Controllers/VolunteerController.php
+++ b/app/Http/Controllers/VolunteerController.php
@@ -93,8 +93,7 @@ public function checkOut(Request $request, TimeEntry $timeEntry): JsonResponse|R
 	 */
 	public function storeTimeEntry(TimeEntryStoreRequest $request, Event $event, User $user): JsonResponse {
 		// Don't allow an ongoing entry to be created if there already is one
-		$input = $request->safe();
-		if (!isset($input['stop'])) {
+		if (!$request->filled('stop')) {
 			if ($user->timeEntries()->ongoing()->forEvent($event)->exists()) {
 				return response()->json(['error' => 'User already has an ongoing time entry.'], 409);
 			}
diff --git a/app/Http/Requests/TimeEntryStoreRequest.php b/app/Http/Requests/TimeEntryStoreRequest.php
index 83b759d..ad055c4 100644
--- a/app/Http/Requests/TimeEntryStoreRequest.php
+++ b/app/Http/Requests/TimeEntryStoreRequest.php
@@ -43,8 +43,13 @@ public function rules(): array {
 	 */
 	public function passedValidation(): void {
 		$this->merge([
-			'start' => $this->date('start')?->timezone(config('app.timezone')) ?? now(),
-			'stop' => $this->date('stop')?->timezone(config('app.timezone')),
+			'start' => ($this->date('start')?->timezone(config('app.timezone')) ?? now())->toISOString(true),
+			'stop' => $this->date('stop')?->timezone(config('app.timezone'))?->toISOString(true),
 		]);
+
+		$this->validator->setData(array_merge($this->validator->getData(), [
+			'start' => $this->input('start'),
+			'stop' => $this->input('stop'),
+		]));
 	}
 }