After a lengthy export job coming back to my Computer to discover that the preview was ... looking interesting to say the least (see attached screenshot). You can, if you know what the image is supposed to look like faintly detect patterns from the original image in the mess. The source files are not corrupted, Smart Previews are not used and I have cleared the Camera Raw cache.
After some trial and error I found out that disabling GPU Acceleration in settings instantly fixes the preview, and turning it back on breaks it again.
Given that GPU Acceleration worked before, I'm wondering why and how this can suddenly appear.
I assume you have a 2019 Macbook Pro 16"? With Macs, you can't update to the latest graphics driver from the manufacturer but instead have to rely on Apple releasing an udpate. But Adobe usually does a pretty good job of coping with driver bugs in Macs, since there's a limited number of drivers to test with.
I recommend you post a bug report in the official Adobe feedback forum, where Adobe wants all bug reports and feature suggestions:
Be sure to include the first ten lines of the menu command Help > System Info. Provide all the details, rather than linking back to this thread -- experience shows that Adobe developers tend not follow the links.
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