I have 2 bluetooth devices connected at the same time, headphones and audio buds.
You can use the Android bluetooth setting to choose which is active (ie you want to play the music).
When playing a song on Plexamp and then switching between the 2 devices Plexamp sometimes plays a track at what appears to be double speed, if you switch back to original device it typically then plays at normal speed but then switching again it goes double speed.
I have tried the bluetooth switching with other apps like Youtube Music and haven’t experienced this issue.
I’ve heard rare reports of this, but there’s not much we can do about it, Plexamp itself isn’t changing the rate of playback, so it’s either a low-level audio library issue or an Android issue.
You can see playback running quicker in plexamp when you look at the playback screen and the seconds moving quickly, don’t know if that helps - I could probably do a screen capture.
Just surprised other apps aren’t affected if it’s an Android OS level issue.