Continuity mistake: When Mario, Toad and Luigi are driving to the rebel fort, the seatbelts they are wearing disappear for most of the scene. (00:17:30 - 00:18:40)
Continuity mistake: In season 1 Hobbie was 13 and in season 2 he is 10 years old.
How the Tess Was Won - August 5, 1956 - S1-E5
Continuity mistake: Though he's leaped into someone else, we always see Sam as Sam, dressed in all the host's clothes (including glasses or sunglasses). His host is revealed only in reflections. But here, when he looks at his host-self in the mirror, the hat and clothes are all identical - except that the reflection is wearing glasses, and Sam isn't. (00:43:00)
Ranma o gekiai! Shintaisou no sukeban toujou - S1-E11
Continuity mistake: When Kodachi gets a faceful of the door, in the shot from the side the hanger with Akane's uniform is missing. (00:23:55)