Photos not rendering properly

Is anyone able to explain what's suddenly happening to some of my photos in Lightroom Classic - see attached image. When working in the Develop module one photo suddenly goes wonky like this - I now have one image looking like this in several folders in my catalog. The offending images appear like this in both the Library and the Develop modules. The images export perfectly but it's pretty hard to edit them. I have tried quitting and re-opening Lightroom but that didn't solve the issue. Lightroom Classic version 14.1.1 on a Mac M1.

Cheers,

Graeme

[moved from bugs to discussions according to the community rules - Mod.]