The first time I tried to put the new nails on a sim's fingers, it caused colourful stripes on the sim's top like sloppy cc with overlapping textures. I figured, okay, maybe it's just this one top, let's go with simple nails for the everyday outfit and save the elaborate ones for more festive getups.
The same thing happend with every outfit that sim wore, and none of them were cc. Haven't used the official nails again since, and switched back to cc nails that don't have this problem. So yeah, I'd say the official nails are indeed lacking - in quality, in testing. As usual.
