Early in the episode Chief Vick says that if they can get to Herb Pollack before Rizzo does, then they will be able to "put this lowlife away for a Very long time" but later when Shawn has a flashback, she just says, "put this lowlife away for a long time." A strange mistake for a psychic with his memory.
In this episode "Stumpy" is a high school friend of Lassiter, but in S04E04 "Stumpy" is a high school friend of Shawn and Gus. It's possible that they both had friends named "Stumpy", but most TV shows/movies don't have multiple characters with the same name.
When the women are getting ready for the wedding ceremony Chief Vick is talking about how her husband does sweet things for her. She mentions her husband entering her hospital room and placing their newborn son gently on her chest.
1) Chief Vick's only child is a daughter.
2) Her husband wasn't present at the birth of their child - Lassiter was.