Super Bike / A Mile in My Shoes - S2-E6
Other mistake: When Jorgen does wand-ups to Cosmo and Wanda, he counts 1,2,1,2,etc, yet when he does them to Timmy, he counts 1,2,3,etc.
Injustice For All (2) - S1-E19
Other mistake: Unless he escaped prison, it makes no sense for Copperhead to be in the police van with the other Secret Society members. You can see him sitting there across from Solomon Grundy and The Shade.
Other mistake: Two Tiffs can be seen for a few seconds when King Dedede and Escargoon drive in.