When Jennyanydots is showing the marching roaches to the other cats, the roaches suddenly appear on the table despite not being there in the previous shot.
Despite the characters being explicitly of the species felis catus, and having established sexes, none have visible anuses, nipples, or genitals, which - with the exception of the cats in clothes - would be notable if not prominent in certain scenes, especially considering the poses and maneuvers that they make.
A few calico cats, including Mungojerrie, are male. Although the nature of chromosomes causes most calico cats to be female, it is a little known fact that male calico cats can exist, although they are extremely rare.
At 49:17, during the Ball opening dance, the camera shows Victoria from directly overhead and her tail is missing. The camera then changes to the side and her tail is back behind her.
Before the final showdown Macavity states to Old Deuteronomy that there are "no cats left" which he concludes makes him the Jellicle choice. This is incorrect, since Rum-Tum-Tugger, who also sang a song, is never actually stolen away by him and is seen throughout the movie and even the scene before, dancing with everyone else.