We already have this tracked on GitHub but unfortunately I have no idea why this happens. Android 11 changed something related to their media notifications. Until this is fixed, Android has a setting to stop displaying the notification as soon as the media session ends (it’s somewhere next to those notifications).
That’s interesting. Not sure if it fixes all cases, though (I can reproduce this even when pressing just play+pause on one single episode). I will have a look if the deletion setting has an influence for me, too.