In the case file for the death of Laura Moser, Dexter's mother, it lists her date of death as October 3, 1973. All Dexter series use Michael C. Hall's real birthday, Feb 1, 1971, as Dexter's DOB. This would've made Dexter 2½ at the time of his mother's death, like was shown in the original Dexter (2006) episode depicts, not the actor's obvious older age of 4 that Harry stated in a previous episode.
When Dexter is searching Captain Spencer's apartment, he comes across a document for a motion in his divorce case, the headline on the document says Supreme Court of the State of Florida. However the Florida Supreme Court does not handle divorce proceedings, it is the state's highest court and final arbiter of the state law of Florida and the Florida State Constitution, and the penultimate arbiter of the United States Constitution in Florida (second only to the Supreme Court of the United States). Divorce proceedings are carried out in circuit court, in Miami they are specifically handled by the Family Division of the Florida Circuit Court for the Eleventh Judicial Circuit. Any appeal of a ruling made by a Miami Family Circuit Court judge would be made by the Florida Court of Appeals for the Third District, the Court of Appeals is almost always the final arbiter of civil matters such as divorce.
A ruling made by the Florida Court of Appeals regarding a divorce proceeding can technically be appealed to the Florida Supreme Court, if it somehow violates the law or a person's constitutional rights; but it is extremely rare, in the last 180 years there are only two documented cases of the Supreme Court hearing an appeal of a divorce case, and the last one was in 1950.
A ruling made by the Florida Court of Appeals regarding a divorce proceeding can technically be appealed to the Florida Supreme Court, if it somehow violates the law or a person's constitutional rights; but it is extremely rare, in the last 180 years there are only two documented cases of the Supreme Court hearing an appeal of a divorce case, and the last one was in 1950.
The arcade game Dexter is playing on has a modern flat screen instead of a curved CRT display which would be common in 1991.
During the search for Laura Moser and her two kids, there is an aerial shot of the harbor where you can see a shipping container from French company CMA CGM. However, while its predecessors existed before, that company was established only in 1996.
Harry's code requires that Dexter be absolutely certain of a person's guilt before killing them. Even though he was already relatively certain about Captain Spencer's guilt, Dexter could have confirmed it with absolute certainty by testing some of the blood he drew from Spencer for the blood drive, against the blood found on the outside of the box Nicky's finger was in.
Spencer mispronounces Glenfiddich. As it is Scottish, the 'ch' is pronounced with a 'kh' sound.
The baby playing Debra as a newborn appears to be Hispanic or Latino.