Playback notification persists after app is closed

Vanilla Music Version (Settings -> About): 1.1.0
Android Version: 11
Phone vendor / model: Google Pixel 3
Application was downloaded from (use [x]):
- [ ] Play Store
- [x] F-Droid
- [ ] Other (Nightly Build)
Did this work in a previous version?
- [ ] Yes
- [ ] No
- [x] NA / Don't know.

Description

After Vanilla Music stops playback and is closed, very often (but not consistently!) the notification with music playback controls is still shown. If swiped away, it simply returns as soon as the notification area is pulled down again. This is despite the Media player in Quick Settings being turn off (so the notification should never appear after the app is closed).

Re-opening and closing Vanilla Music a bunch of times seems to eventually make the notification go away. But sometimes it might re-appear a while, sometimes hours later.

I believe the Media player in Quick Settings was a setting introduced in Android 11. As for the Vanilla Music version this affects, this might have started happening in the previous version (1.0.92), but I'm not positive (should have reported the bug when I first noticed it last month, sorry). I know it wasn't a problem that started when I upgraded to Android 11 itself, since I've been using 11 since last fall and the issue has only happened since sometime in April.

I've also noticed that even when closed, Vanilla Music is sometimes (again, not consistently) still considered active by the OS and uses up battery power. Today, for instance, I had it closed since the night before and didn't use it at all after charging my phone, but it appeared on the apps using battery power. I'm not sure it is related to the notification issue (since it wasn't visible today), or a separate bug.

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Steps to reproduce the issue

Confirm the "Media player in Quick Settings" toggle is set to off. Open Vanilla Music and play something. Stop playing music. Close Vanilla Music. See the persistent playback notification. ...

Screenshot / Video (If applicable)

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vanilla-music / vanilla