Family Ties - S4-E17
Revealing mistake: After the New Men have captured Magneto, Wolverine, Scarlet Witch and Quicksilver, the establishing shot of the High Evolutionary's headquarters is a recycled shot of when Scarlet Witch and Quicksilver first arrived at his headquarters a few minutes earlier in the episode, played on a loop (note the lightning strikes and the High Evolutionary's pink energy field being repeated). (00:05:35 - 00:12:40)