Kick-Off for the Future - S1-E3
Other mistake: Urabe mentions that Nankatsu lost to Shutetsu 30 to 0 (which seems rather uncanny for a 40 minutes match), but the score mentioned in the first episode was 10 to 0. The more extravagant result ends up being the canon one.
Other mistake: When Teela is at Snake Mountain, she overhears TrapJaw saying how Skeletor's electrical creature will control all of the machines at the palace. When Teela returns to He-Man, she says that the creature Skeletor created is called Byte. There's no way for Teela to know the name of the creature, since TrapJaw never referred to it by name. (00:14:24 - 00:15:20)