Revealing mistake: When Nathan and Audrey are sitting at the table in The Grey Gull, the extra in the background can be seen bringing a loaded fork inches short of his mouth then fake chewing. This happens a few times before cutting to the ending credits. (00:40:05 - 00:40:55)
Audrey Parker's Day Off - S2-E6
Factual error: When Audrey turns on the car radio to listen to the baseball game score, the LCD display turns to the time. When she turns it off, it shows the tuner. This is the opposite of how car radios function - the sound editor must have been dubbing in the sound, and missed this).
Continuity mistake: Almost at the end of the show when the reverend is walking uphill towards his wife (who he thought was dead) the van door was closing, then shut, the driver of the van was already in and shut her door. When they show the reverend's face, then the van again, people are still getting in the van, and the driver too.
Character mistake: Nathan suggests to Dwight and Audrey that maybe he should shut down the meeting of troubled people. As chief, he should know he has no authority to stop citizens from assembling.