I am having the same issue, I am loosing the cover art. When I force update metadata and images and select don't copy of existing it copies the 10s of thousands of art work and video. Some categories are fine others lose there image again. I updated to 11.12 and this started happening. Any ideas?
I have 42 buttons just purchased in Dec. I am not seeing the valence in the white that you are seeing. These buttons aren't as bright as others but it was a trade off for the gold leaf switches. I had one go bad during installation but it was a wire pulled loose which is fixable. The handles on the servo sticks are definitely not as bright and have a magenta hue to the white. The trackball is not a bright white but it stills good and love that I can change the color scheme on the fly. Will upload pictures later.