Android/Pixel 6
Unlocking screen when the Deezer app was left open causes the player to skip backwards in playlist. Sometimes to the top or back to when the device was last unlocked. Works on any playlist/album and even Flow and the bug is recreatable.
Simple work-around I found is to minimize the app before locking device.
I've known of this bug for a few months now but I don't know if is a known issue or specific to my device.