Robo Koopa - S1-E52
Revealing mistake: When Bunsun walks up to Dr. Nerdnik to free him, an animation mistake is noticable. Bunsun is far away and she walks up to him, and during this whole sequence her body is in front of Dr. Nerdnik, according to the camera's view. (00:04:55)
Shanpû no hangeki! Hissatsu shiatsuken wa mimo kokomo ubau - S1-E16
Revealing mistake: In his close-up when he grins at Ranma after his request to help him figure out what happened to Akane, Ryoga is drawn really obviously with the hair going under his eyebrows. (00:15:00)