Other mistake: The episode's action takes place around 11:00pm (night time), yet all the scenes show broad daylight.
Other mistake: After King Tut's men deliver the statue, it's referred to as a Sphinx. Even Batman says, "Rather good imitation of the 4th Dynasty's Sphinx at Giza." Problem is, the Great Sphinx of Giza is a reclining lion with a human head. The statue in Gotham's park is a ram's head atop a seated human body, resembling Egyptian God Khnum, and looks nothing like the Egyptian Sphinx. Bruce Wayne is a member of Gotham City Museum's Board of Trustees, which recently opened the new exhibit of Egyptian antiquities. (00:10:35)
The Revenge of Robin Hood - S1-E16
Other mistake: Robin Hood and his men ambush the king's cavalry as they ride by the group, but all the arrows hit the riders frontally in the chest - the arrows should be striking home on the left sides of the cavalry troopers.