When Holt and Jeffords are arguing over the train set, the small pieces of trash on the set change positions in different shots and are even gone in a couple of the shots.
When Amy and Jake are on the building roof, there is a fire hose reel with the hose completely rolled up. A few minutes later when Jake goes to "Die Hard" off the roof, the end of the hose is hanging down and resting on the roof.
When Terry is describing "Jefford's Junction" train set to Holt, he mentions a sombrero shaped restaurant. Initial shots of the train set do not have the restaurant on it. The camera cuts to Holt for a moment, then back to the train set and the restaurant is there. Not enough time had passed for Terry to get and then place the restaurant.
Jake initially explains that if Amy fails the sergeant's exam, she will not be able to retake it for 3 years, which could mean that Amy will be personally ineligible to retake it for a 3 year period. Amy later says that if she doesn't take the test this time around, she will take it in 3 years, implying that the exam is only given by the NYPD once every 3 years. The actual sergeant's exam by the NYPD is given yearly. Amy could take the exam the following year. The actual exam is also 4.5 hours, taken across 2 days, not a single 2 hour session as portrayed here.
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.
Jake states that it is 78 degrees outside, but he is wearing 3 layers (shirt, hoodie, and leather jacket), Rosa wears a leather jacket, and people on the street are wearing winter clothes. This is not the appropriate clothing if it was 78 degrees.
Gina says that the Boyle trip to Aruba was "the worst," as "all 18 of you" (Boyle cousins) had sleep apnoea. In Skyfire Cycle (2016), only 16 Boyle cousins (including Charles) were going to Aruba.
Gina places the Boyle sourdough starter near her space heater and it is destroyed by the heat. Terry made her get rid of her space heater in The Overmining (2016) to help reduce the precinct's energy usage.
Captain Holt describes the train set's "little house" as "a work shed where the yard men get their OSHA mandated eight hours of rest between shifts." While railway yard workers might spend OSHA-mandated work breaks DURING shifts in such a hut, they undoubtedly use their minimum eight hour rest BETWEEN shifts to go home to bed, like everybody else does.
When Gina refuses to give Charles the mother dough, she says she's going to start baking. However, in an earlier episode (Ebony Falcon Season 1, Ep. 14), Gina keeps Amy awake all night using Amy's bread maker.