Continuity mistake: When we see the "Lump Massager" at work on the lump on Wile E. Coyote's head, you can see that there are three valves on the machine, but when we see Wile E. at work on his drawing board in the next shot, there are now two valves on it.
Continuity mistake: When Daffy Duck is printing fake rabbit tracks at the beginning of the cartoon, he puts two tracks next to Bugs Bunny's hole. But when Elmer Fudd arrives at the hole, the two tracks have disappeared.