Audio that can't be paused due to lack of controls

Hello.

Having another app in foreground makes the audio controls disappear while audio continues.
When switching back to Nextcloud News there is no way to stop the audio, or restart it if it stopped by tapping the audio controls in the notfication area. This only happens from time to time.

Also, sometimes the audio controls seemingly disappear for no reason when looking at other posts of the feeds. This means that there is no way to stop audio other than force-closing the app or rebooting the device.

When I play another audio file I then have two files playing simultaneously. Pausing that pauses both. Resuming resumes both. The only way to continue with a single audio file seems to be rebooting the device or waiting for one on them to end.

Version: 0.9.9.75 from F-Droid (though the issue has existed for a while now)

No source files, tests, or entry points are identified. Start by reproducing playback while another app is foregrounded, from notifications, and while switching between feed posts; done means audio controls remain available and starting another file does not leave multiple files playing.

Written by the indexing model from the issue text.