Timer staying present on Dynamic Island

Close the Clock App:

How to close an app

1. From the Home Screen, swipe up from the bottom of the screen and pause in the middle of the screen.
2. Swipe right or left to find the app that you want to close.
3. Swipe up on the app's preview to close the app.

Close an app on your iPhone or iPod touch - Apple Support (IN)

This does not solve the issue. The timer is staying on the dynamic island for over 24 hours at this point. Closing the app does nothing. Only restarting the phone will remove it. And then as soon as you use the timer again it remains in the dynamic island until you turn the phone off. Even using other features that should show on the island (like Spotify or phone calls) do not displace the timer.