diff --git a/packages/snaps-controllers/src/cronjob/utils.test.ts b/packages/snaps-controllers/src/cronjob/utils.test.ts
index ad7e149d96..2344040c84 100644
--- a/packages/snaps-controllers/src/cronjob/utils.test.ts
+++ b/packages/snaps-controllers/src/cronjob/utils.test.ts
@@ -62,6 +62,10 @@ describe('getExecutionDate', () => {
     expect(() => getExecutionDate('100 * * * * *')).toThrow(
       'Unable to parse "100 * * * * *" as ISO 8601 date, ISO 8601 duration, or cron expression.',
     );
+
+    expect(() => getExecutionDate('P1000000Y')).toThrow(
+      'Unable to parse "P1000000Y" as ISO 8601 date, ISO 8601 duration, or cron expression.',
+    );
   });
 
   it('throws an error for dates in the past', () => {
diff --git a/packages/snaps-controllers/src/cronjob/utils.ts b/packages/snaps-controllers/src/cronjob/utils.ts
index 1d61fa7f9c..2ff44db0cc 100644
--- a/packages/snaps-controllers/src/cronjob/utils.ts
+++ b/packages/snaps-controllers/src/cronjob/utils.ts
@@ -65,14 +65,16 @@ export function getExecutionDate(schedule: string) {
     });
   }
 
-  const duration = Duration.fromISO(schedule);
-  if (duration.isValid) {
-    // This ensures the duration is at least 1 second.
-    const validatedDuration = getDuration(duration);
-    return DateTime.now().toUTC().plus(validatedDuration).toISO();
-  }
-
   try {
+    const duration = Duration.fromISO(schedule);
+    if (duration.isValid) {
+      // This ensures the duration is at least 1 second.
+      const validatedDuration = getDuration(duration);
+      const offsetDate = DateTime.now().toUTC().plus(validatedDuration);
+      assert(offsetDate.isValid);
+      return offsetDate.toISO();
+    }
+
     const parsed = parseExpression(schedule, { utc: true });
     const next = parsed.next();
     const nextDate = DateTime.fromJSDate(next.toDate());