Other mistake: The FBI agents call for a taxi and official transportation from the Evans apartment and gave the address of 963 North Gilbert. However, the Evans lived at 921 North Gilbert. Since the FBI was at their apartment, you would think that they would know the address or exactly where they are in a Chicago project. (00:13:03 - 00:28:29)
Character mistake: James mentioned to Florida that he always knew his father was alive (after claiming to Florida he was dead in the past). But since James hasn't seen or heard from him in 35 years, there would really be no way for James to know that his father was still alive for sure - more like just a guess than certainty.
J.J.'s Fiancee: Part 2 - S3-E18
Continuity mistake: At the beginning of the show, JJ's girlfriend is wearing a shawl and the buttons are miss-buttoned by one button. In the next scene, the shawl is buttoned correctly.
Answer: Carl did die of lung cancer, that's why she returned to her family.