Farewell My Beloved Witch - S1-E3
Other mistake: The professor gets killed by Stern's machine gun, but he was inside the plane and the plane suffers not a single bit of damage. A stray bullet can go anywhere, but at least one of the other bullets should have hit the fuselage.
Farewell My Beloved Witch - S1-E3
Other mistake: In the first part of the episode, the Third Sun is purple when in the hand of the characters in close-up, and pink in the field. Different shades of pink, some quite dark, but never the same shade as the close-ups or even close.