Launch Party - S4-E3
Continuity mistake: In 2-13 "The Secret" Pam and Jim are talking about how Jim used to have a crush on Pam when she first started here. This implies that Jim was working here when Pam was hired. However, in this episode Pam says that when Jim first started working there she said, "Enjoy this moment, because you're never going to go back to this time before you met your desk-mate, Dwight." These two scenes contradict each other.
Answer: In the 2007 episode "Ben Franklin" when Jim is talking to Pam there is a candy bar with a purple wrapper that says "Picar-" I assume picaroon, it's hard to see past Pam. I found this trying to investigate what that candy bar is lol.