When Nellie, Toby, and Daryl are in the break room, discussing the Scranton strangler, Nellie and Daryl are reading newspapers. Nellie's paper changes between shots.
When Pam is at her interview, the manager is singing that she's been at Dunder Mifflin for 8 years, and later in an interview, she says that she was a receptionist to Michael Scott for 10 years,
Like Michael Scott, the real estate manager is prone to making mistakes like not being able to do simple math.
When Andy goes into his office and shuts his blinds, the left blinds are turned down. The camera quickly cuts away, then looks back at Andy, where you can see the left blinds are now turned up.