Thanks for the update, but this doesn't seem to help. For me it is easy to reproduce:
Start Poweramp, go to the library, select a playlist, and press the shuffle button.
Let the music play for a little while (a few seconds should be enough).
Pause the music (and wait a little).
Open the recent apps list, and swipe away Poweramp.
Start Poweramp again. Initially it shows the correct track, but after 4-5 seconds it jumps to the first track in the playlist (and stops playback if I started it right after re-starting the app).
This on a OnePlus 5T with the latest official OS, no Bluetooth involved. Playlist is in WPL format, so it is known to the Android media library. It only happens when playing playlists, not when playing an album or all songs. Let me know if you need more information (adb logs or similar).
Worth noting is that I couldn't (easily) reproduce it with an app exit until fairly recently (around version 800). It still happened, just not very often.