Heart of Ice - S1-E3
Other mistake: Batman uses a thermos full of chicken noodle soup to defeat Mr. Freeze, and moments later gives Summer Gleason a security tape that incriminates Ferris Boyle. When Batman pulls out both of these aforementioned items, there is a corresponding clicking sound that suggests he pulls them from his utility belt, but both items are far too large to fit inside the belt. They also could not have been simply been hanging from his belt, as Mr. Freeze had possession of Batman's belt a few minutes prior and they were not there. (00:20:05 - 00:20:45)