The Night of the Bubbling Death - S3-E1
Revealing mistake: As West drags the body of a bad guy out of the scene, the supposedly unconscious man is holding his head up so as not to have his head dragged through the dirt. A truly unconscious person's head would flop back on to the ground.
Urutora sakusen dai ichi gô - S1-E2
Revealing mistake: The VTOL hits Bemular with two missiles the second time that Hayata makes him come out of the water. The second missile causes an explosion with the special effect applied in the wrong spot, a spot in the back of the monster that is practically the opposite of the direction in the line of shot. (00:17:50)