In the episode where Arnold and Helga are the best spellers in the school is where you can find this slipup. At the All City Spelling Championship, they show Gerald saying, "No kid can spell pasquinade." It shows that he has 2 drinks, but after the kid spells the word, (he was cheating) they show Gerald again, and he only has 1 drink and popcorn. Then they go back to the stage, and Arnold and Helga are the only ones left. When they go back to Gerald, he has no snacks at all, though he had them 10 seconds ago.