Coming Home - S4-E1
Deliberate mistake: This scene between Dawson and Jen in his 'dark room' was shot in a distinctive red light. However, in reality there was no red light during filming, the effect was added later during post-production. (00:19:25)
Deliberate mistake: During this scene when Dawson and Joey are getting ready to graduate, the actor James Van Der Beek asked to ad lib his dialogue. He did, and what ended up on the air was his improvised version of the lines that had been written in the script. (00:39:30)
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.