Other mistake: When Sam tries to bring Bugs down from the crows' nest/elevator, he pushes the "Up" button and brings it down.
Continuity mistake: When we see the rowing boat on the beach at the beginning of the cartoon, you can see that the oars are standing straight and the boat is on the sand. But when Bugs Bunny takes the boat to escape from Sam, the boat is in the water and the oars are now in the rowlocks.