When Ron and Andy are eating their burritos and talking, Ron has a tray of food next to him. When Andy throws the ball over to Ron, between shots the amount of food in the tray by Ron changes. Some of it disappears, but then reappears as Ron gets up out the chair.
When Tom is introducing Leslie for the Chamber of Commerce, the binder in Leslie's lap switches from sitting upright against her stomach to flat on her lap several times.
Influenza, a respiratory illness caused by a virus, rarely involves gastrointestinal distress, but everyone is acting like they have a bacterial infection from food poisoning. This is a common factual mistake.
When Ron visits April in the hospital, you can see part of a boom mic in the top right corner of the screen as April asks him to not tell Andy she's in the hospital.
Leslie is admitted into the hospital for having a fever of 104° and for being dehydrated, but she never has an IV while she's in the hospital.