It's All Greek to Scooby - S2-E13
Continuity mistake: After the Centaur falls of the scaffoldings, Fred, Daphne and Velma climb up and are seen standing straight up while Shaggy is putting the medallion back in his shirt. It cuts to just show them and suddenly Fred has his hands on his hips, Daphne is dusting herself off, and Velma is bent over trying to catch her breath. (00:06:15)
It's All Greek to Scooby - S2-E13
Continuity mistake: When the gang is talking to Major Portsmouth, there is a guard sitting at a desk with his legs propped up on the desk. A lamp is on this desk. A few shots later when seen from above, the lamp has vanished. (00:07:15)
It's All Greek to Scooby - S2-E13
Continuity mistake: The gang catches a ride on a boat and have to find room in the animal storage area. Shaggy and Scooby are shown sleeping next to the sheep. But when Lysander walks in, they are next to the goat. (00:10:35)
It's All Greek to Scooby - S2-E13
Continuity mistake: When the gang gets to Santorini, the centaur shows up again and they take off to the right following the wall. Then the 'old maniac Moped guy' comes at them from the right going left. So they are going right, the Centaur is behind them to the left, and the Moped guy is to the right. So they go into a doorway between them. The Moped guy comes from the right and goes to follow, then suddenly the Centaur comes from the right also, when he was on the left. (00:16:40)
Answer: Because of the goo that was on it.