When Danny and Jackie are interviewing the family of the woman who possibly committed suicide, the woman's brother argues with Danny and tells him to investigate the woman's boyfriend. As he faces off with Danny, he finishes his dialogue with his hands in front of him. However, the next camera shot focused on Danny shows the man with his right hand up and pointing in Danny's face. Also, you can see the side of the man's mouth moving (like he's still shouting), but you don't hear any more dialogue from the man.
Despite taking a high-profile undercover assignment, Jamie keeps in touch with his family and even continues to visit them in person. No police department would ever permit this.
When Henry is thanking God for his blessings, when he says "Dr. Durell", his mouth is clearly saying some other name.
Erin mentions that she is an Assistant District Attorney for New York City. Each borough (or county) in New York City has its own District Attorney. Erin works for the New York County (Manhattan) District Attorney.