Reminders widget not sync after action with notification banner

First, check whether the problem is specific to the Reminders widget, or if it also appears in the Reminders app itself. Open the Reminders app directly and see if the reminders there are updating correctly—especially when your shared lists are involved.

Next, when you receive a reminder notification and mark it as completed directly from the notification, open the Reminders app afterward and confirm whether that task is properly marked as completed within the app. If it still shows as incomplete, that’s a key clue.

Also, keep in mind that reminders synced through iCloud or other email accounts require an active internet connection to update across devices. Make sure your iPhone is connected to Wi-Fi or cellular data and that iCloud syncing for Reminders is turned on in your settings. You can find this by going to Settings > [Your Name] > iCloud and ensuring Reminders is enabled.

Finally, observe if this behavior is happening only on shared lists or across all your reminders.

Jules_Fal wrote:

Since iOS 18 the reminder stays in the widget (I waited a long time) until I open the reminders app or until I mark it as done (again) on the widget itself.

It's not always the iOS update's fault!  Many things can cause phone problems.  If you tell people you think it's an iOS update, it might make it harder to fix or find a solution for the real issue.

Remember, the right question often leads to the solution!

Was/Is your device Jailbroken? If that's the situation, please be informed that attributing the issues to iOS updates may not be accurate.

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. The majority of the issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: About iOS 18 Updates, About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...

Hey! I had a similar issue.

I went to my reminders app and sorted by due date and the widget refreshed.