Aha! It does seem to be a Firefox problem. When I had the same session open in Firefox, I continually got no help from the AI identifier. I uploaded the same set of photos in Chrome, and AI worked fine. I restarted Firefox, and then Firefox worked fine again with the same set of photos. Something in the Firefox cache perhaps, something that got cleared when I stopped and restarted Firefox?
In any case, the glitch seems to be with Firefox, not with the AI system.