Continuity mistake: If you notice, Robbie's puppet "Rex" is bigger in this episode. (His head is huge.) But for the rest of the show his head is smaller.
Factual error: PJ is getting his hair cut by an attractive female barber. Attached to the outside of the window is a neon sign reading "BARBER SHOP," but the sign faces the inside of the building so it would be backwards to people outside.
Speeding Is Dangerous - S1-E22
Other mistake: When Shine says, "I think I'm OK," his front tire is layered over the railway tracks.