Today I imported a card with about 150 images and I was going through in develop mode making some quick changes and ratings. I fumbled a key slightly and one of the images turned completely grey and won't correct itself. I turned LR off and on again and issue persisted. The image is on my hard drive and can be previewed there through my Mac software. I have an iMacPro, OS 10.14.3 and am running LR Classic 8.2.1. This is relatively alarming for fear it will happen again in the future. Screenshot saved.