Images in photoshop being distorted when disconnecting Wacom tablet?

Hi guys,

When disconnecting my Wacom tablet (16") from my iMac (with photoshop still open) the images I have open that I’m working on in photoshop are becoming distorted, a quarter of the image will remain unaffected whereas the bottom half will turn into long lines (attached screenshot). If I move the image around the interface the lines will remain but just change in colour, so they're not fully embedded into the file, and I'm assuming they're not actually saving into the file, just an odd affect that's happening at the time. I’ve tried duplicating the file, zooming in and out with it, and they still remain.

The only way to get rid of them is to plug my tablet back in, or close photoshop and re-open the files (quite annoying). 

*I often have to plug and unplug my tablet, as I use my desktop for other things and when the tablet is plugged in it lowers the quality of my iMac screen (and zooms in) so I prefer to keep the tablet unplugged when not in use*

Any idea of what might be happening? I’m using photoshop 2021 (reluctant to update until a bigger update, as every time I update I seem to get so many new bugs/errors and can’t quite afford that right now due to a deadline).

This only started happening very recently, in the past I was constantly unplugging/re-plugging my tablet with no issue at, nothing would happen to the files I have open (as expected). 

Thanks!