iBooks keeps starting at the wrong point

Just recently, whenever I open iBooks and continue with my Audiobook, it starts at a point I listened to in the past. Its always the same point, Chapter 7. There appears to be a little dot on the Audiobook timeline, as if I have somehow put a marker there but I cant remove it.

I have an iPhone X and I am running the latest software (I just updated and hoped this would solve but hasn't). I have done a hard reset and closed the app, all the usuals.

Any suggestions? Its annoying as ****, I basically have to remember where I am up to every time I stop listening because I know I'll have to manually skip there once I start up again.