The Bermuda Triangle Crisis - S2-E4
Revealing mistake: When Wonder Woman drops a mine into the water, she's supposed to be dropping it into the ocean. However, you can see a drain plug of some sort in the background and the "ocean" is obviously a pool, or similar.
The Return of Bigfoot: Part 2 - S2-E1
Other mistake: Sasquatch's black wig does not match the color of his brown fur suit.