Continuity mistake: When Granny and Tweety are resting, Sylvester grabs Granny's glasses and paints a picture of Tweety on the right lens. When Granny puts on her glasses after she hears Tweety calling for help, the picture of Tweety is now on the left.
Continuity mistake: When we see Junyer Bear sleeping in bed at the start of the cartoon, you can see he has "Junyer" written on the end of his bed, but when he is sitting up a couple of shots later, the word "Junyer" has disappeared.
Continuity mistake: When Spike is eating the leg of ham, the glass on the tray is empty. But when Drippy arrives at the table, the glass is now full of beer.