In my case, it was still listing images that were only tagged with white_legwear+thighhighs in the list of white_thighhighs. You click on the image, and the latter tag wouldn't even be there.
However, now I'm just seeing images that are actually tagged with white_thighhighs as if the alias is broken, including post #890620 which was uploaded 1 hour ago...I'm glad I didn't go into the career of database management, honestly.