Continuity mistake: Molly was not informed and arrives at the first writer meeting 2 hours late, carrying cupcakes. She puts the 3 boxes on the table. The stack is at one point suddenly perfectly aligned (when Katherine asks her "What do you think?" but the pieces are again not perfectly lined up just after. (00:18:55)
Continuity mistake: The group of writers is prepping for the job interview with the young brother of one of them. Hayes as he listens to the instructions is keeping his hands in front of the chest in the close-ups, which is not reflected in the side views, when his arms are always down his sides. (00:06:45)
Continuity mistake: At the beginning of the movie, in the scene when Katherine ends up firing the writer who asked for a raise, check out her assistant: he is reflected in the glass behind Gabe Eichler, and his posture as he gets uneasy when Katherine starts blasting the writer is often different between the front views and the reflection. For instance when she says "You are fired, obviously" Bradley is looking up, arms folded, but touches his face in the reflection. (00:04:40)
Revealing mistake: The camera holds on a close-up of the article featuring the 'Female President of the Network' Caroline Morton for 3-4 seconds, long enough to allow to quickly browse the text and easily see that it's a generic article about women in workplaces used as filler text and not the interview Katherine is reading. (00:03:25)
Character mistake: During her initial monologue, Katherine Newbury does the obligatory joke a 'foreign' host would make, rethorically asking where the good 'murican hosts are instead. Doing so, she mentions Martin Short, Jerry Seinfeld, Alec Baldwin. However, Martin Short is a bad example in the context of the joke, being Canadian-born.