When Dexter walks back into the Mitchell house and asks Jonah what happened to his finger, Arthur is seen holding a beer glass. In the next shot of Arthur, he is eating nuts out of his hand, and no beer glass is visible in his hand or on the table.
Arthur and Dexter are rummaging through the garage to find the football to toss before the game starts. Dexter finds the football that is deflated. Dexter can be seen tossing a fully inflated football into the air when they leave the garage as Jonah pulls up in the damaged Mustang. Every other shot with the football shows it remained inflated.
When Rita and Eliott are preparing Thanksgiving dinner, grocery bags from Ralph's are visible on the kitchen counter. Ralph's is a chain on the west coast, but the show takes place in Florida.
When Christine walks into the Homicide Department to bring Quinn a pie, she is not wearing a visitors badge.
The football game they watch at Trinity's house is Seattle vs Oakland, neither of which play on Thanksgiving.
Dexter worries about creating Thanksgiving traditions for the kids and asks Rita: "My not going to work, will that ... misshape them?" When in fact he is just about to go to "work". Him not being there is what worries him. So he should have said "My going to work ...".
When Batista visits the husband of a murder victim in the hospital, he is told the patient is in a vegetative state. However the patient can be seen with his eyes wide open at one point.