When Sandy and SpongeBob first try to enter the Salty Spitoon, Sandy rips off the bouncer's tattoo, flips it, and puts it back on. Later in that scene, the tattoo returns to normal.
When Reg says "Oh, yeah! Check out the new ink!", the rainbow wig (with which SpongeBob disguised himself a moment ago) is seen shifting unnaturally due to an animation error.
When Squilliam asks SpongeBob his name, he doesn't know it as it is emptied from his mind. However, earlier after serving Squilliam, Squidward addresses SpongeBob by name, and he replies as if he already knows his name.