Surf's Up! Joker's Under! - S3-E10
Other mistake: An amazingly precognizant Dick Grayson is already wearing his surfing togs before Commissioner Gordon calls to say that Joker has invaded the surfing community. (00:04:30)
Suggested correction: Dick isn't amazingly precognizant. He's wearing swim trunks while using the rag to prep his own surfboard. Barbara Gordon was already at the beach with Skip, and Dick is heading to the beach with his surfboard as well (00:04:34).
Other mistake: Jane Webb is listed in the closing credits as "Store Lady". She actually played the "Story Lady". (00:25:00)
The Case of the Missing Monkee - S1-E17
Other mistake: When Peter is tied up at the Remington Clinic, as the camera does a pan from behind him, you can see that he has been tied with a quick-release knot.