Yes Sir, That's My Baby - S1-E19
Continuity mistake: In the scene in bus station, when Mork is talking to the drunk sleeping person, he's holding a bag, there's a shot of the FBI man, and the next shot of Mork, he's not holding the bag anymore.
Continuity mistake: The third years in this series were first years in series two.
A Case of Overexposure - S5-E8
Continuity mistake: In season one episode 16, Arnold says that him and Willis never met their landlord. In this episode they remember him as Mr Darcy - when they see him they recognise who he is.
Pink Arcade / Life With Feather (pilot) / Pink S.W.A.T. - S1-E2
Continuity mistake: Life With Feather (pilot): When the dragonfly is captured in the cage, he is initially standing by the door, but the next shot shows him holding on to the bars at the other end of the cage.