Functions for controlling audiobook no longer working from Lock Screen

I’m using an iPad Air 11-inch (M2).

I was listening to an audiobook and had set the timer for one hour. I closed the cover (the one made by Apple for this iPad). I missed the last 30 minutes of the book so I opened the cover and went to use the slider to move it back but it wouldn't work. I also tried to hit the play button. It also did not work. The screen is clean.

I double checked and these functions work on my iPhone (13 mini also running iOS 17.6).

I’m also having a problem with a white vertical line appearing when swiping up from a locked screen appearing occasionally.

Can someone else to see if they can replicate this?

p.s. I just tried to do it again and the dialogue box for these functions kind of 'crashed'. Images below.