Happens for me too in version 184.108.40.2066 (iOS). It’s pretty consistent from what I can tell.
- play an album on the phone speaker for a bit then
- pause it from the iOS lock screen
- turn off the phone using the side button
the albums starts to play again immediately when the screen turns off.
My workaround has been to kill the app before shutting off the phone and that seems to take care of it.
The solution in this thread to delete the app is a terrible one and very inconvenient (especially that I’m travelling and have some offline music loaded up for the plane). I would appreciate an actual fix for this.