Amy, who was only fairly recently promoted to the rank of sergeant, is given a promotion to deputy chief, completely bypassing the ranks of lieutenant, captain, and commander. The NYPD has fairly strict rules about how long an officer has to serve at one rank level before they can be promoted to the next, and there are qualifying exams at each level. There is no way someone could be promoted the way Amy was.
Santiago is wearing 2 citation bars that are not issued by the NYPD. Also, NYPD regulations require that the American Flag bar be worn as the highest citation bar - something Santiago would have known.
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 moves a large 4-tier wedding cake across a table as though it is weightless.
Captain Holt tells the squad that Kevin has always regretted how rushed their original marriage ceremony was, hence the vow renewal. In Boyle-Linetti Wedding (2015), it was Holt who held some regret for how rushed the ceremony was, while Kevin reassured him that, had it not been so, he would have missed Holt's "efficient/officiant" quip. The two then agreed that the ceremony was perfect and they harbored no regrets.
Jake is upset that his cover identity is named Mitch. In the season 8 opener, The Good Ones (2021), he gives himself the cover identity of Mitchell Keith Erikkson. Mitch is short for Mitchell.