Slowpoke Pics currently has a comparison of all three UHDs of Seven Samurai (1954). The very first screencap, of the BFI disc, shows sloppy retouching:

(Full image here.)

The Toho UHD looks the same, but with different grading, cropping, and filtering. The Criterion UHD doesn’t have these smeary spots, but I don’t know how it looks in motion.