The "adult parties" written on the whiteboard changes between shots.
When Boyle is speaking with Vivan, he looks up and sees Rosa in the middle of the living room mingling with people. A moment later, she is suddenly by herself next to a white set of doors looking into the living room, watching the guests interview Gina.
Captain Holt wears his Commendation breast bar above his World Trade Center Breast Bar. When the WTC bar is worn, it is worn above all other medals, but below the American Flag bar.
One of Jake's pieces of evidence as to why Kevin did not like cops was Hitchcock being asked if he and Scully were discriminated against when some of the other party guests assumed they were a gay couple. Jake was not present for that event.
During earlier episodes, Peralta brags about not visiting the dentist in 8 years. During this episode, he says that he read the New Yorker article on anti-slavery, presumably 4 weeks ago when the issue was new. The shot of him reading The New Yorker was of him in a dentists chair. In episodes later in the season and in other seasons, he will brag about not going to the dentist in 8 years, which in itself is another flaw since time does not stay still during all of the seasons. He always says 8 years, but he had really been to the dentist 4 weeks before Capt. Holt's birthday party.
When going over the reasons why the party is strange, Jake says that "a native English speaker referred to Captain Holt as hilarious." No one had called Holt hilarious. Kevin said that Holt, "had me in stitches," and another guest said, "there's no one funnier than Ray Holt."