After the latest update I have been getting strange large color blocks on the right hand side of the images.
This happens after using the High Pass Overlay Sharpen technique (used for years). At that point it will appear on the layer in the icon pallette. After that, if I crop or duplicate a layer the big blocks appear on the image.
Have trashed the preferences. Have disabled GPU compositing. Has not occured on my M1 Mac Mini.
Is your M1 running Monterrey? There were a few driver bugs in Big Sur that were fixed in Monterrey. If you go to Preferences > Performance and click on the "Advanced Settings" button. Uncheck Use OpenCL, restart Photoshop and try your steps to see if the problem persists. Alternatively, if you upgrade to Monterrey does the problem persist?