Uhura beams back aboard the ship, clearly showing off her six-pack. The shot slipped by the censors. This has been credited to Star Trek superfan Bjo Trimble. She reportedly distracted the observer from Standards & Practices with a long lunch.
It wasn’t just the one glimpse of Uhura in the background though, she was showing off her belly button through the whole episode.
Silly thing to censor in any case given that the entire structure of Starfleet was already based on navel tradition.
