Revealing mistake: When we first see Yosemite Sam at the tiller at the beginning of the cartoon, he moves the wheel back and forth but the capstan and rope do not move even though they are meant to be attached to the wheel.
Captain Hareblower (1954)
1 revealing mistake - chronological order
Continuity mistake: When Sam confronts Bugs by the Powder Room, Bugs takes out a match, lights it and throws it into the Powder Room. You can see that the packet of matches is now one short. When Sam tells Bugs that "If you does that once more, I ain't a-goin' after it!" we cut to Bugs and when he takes out the packet, it is now full with matches again.