A Weekend in the Country - S3-E12
Audio problem: During the scene where the group (including Mr Fricke) are all having breakfast together, Pacey says 'this is for you, Mr Fricke' and hands the B&B critic a plate. A few moments later, when Joey is in the kitchen area talking to Bessie (away from the group in the dining area), the exact same dialogue can be heard from Pacey as background noise to Joey and Bessie's conversation. The laughter and general chatter is also the same, showing that the entire audio was lifted from the breakfast table scene and placed over the kitchen conversation scene.
Answer: It's only explained once in the series. Jack says to Andie "I tried to start kindergarten without you", meaning Andie was smart enough to start school early.