I’m seeing the same issues with an iPhone XR. Additionally:
In this iPhone and an iPhone 4, the Plex app doesn’t show on the lock screen most of the time, so I have to unlock to access the app
When I play music from my local server via the ‘Shuffle All’ option, I often don’t see the track being played in the app’s UI (neither as a footer on the library page or as the full song page)
Same issue. If I move away to another app for any length of time over say, 30 seconds, I switch back to Plex iOS restarting itself (and disconnecting itself from my Chromecast).
IPhone 11 Pro & iOS 15.1 here.
Same issue here. iPhone 11, IOS 15.1, PLEX app 7.26.
Switching app and back again used to work flawlessly until recently. I can’t say whether the IOS 15 or 15.1 upgrade was when it stopped working, but it’s incredibly frustrating!
Update: this also happens if I pause play from the Home Screen and leave it paused for more than ~1 min. I go to the Home Screen again and the play controls square is gone.
It appears that the app crashes in the background.