The iBooks app plays 2 parts at the same time
If I am on the go and first listen via the speakers, then from my car via bluetooth, then on my Airpods when I leave the car this happens: The iPhone plays the audiobook from where I just was and on top of that some earlier part at the same time.
I have had to kill iBooks and restart it to get rid of that cacophony.
Is there some other way?