When Chablis is at the cotillion she asks a woman at the table to watch her purse. After dancing, getting a drink, and leaving, she never retrieves her purse.
In court, when the Detective takes the stand, the area in front of jury is empty/open. When Sonny Seiler starts to question the Detective about the crime scene, a large wooden table suddenly appears in front of the jury box. In fact, when talking about the cat in the crime scene photo, Sonny sits on this table facing the jury. In the very next scene, the table is gone again.
When John cannot start his car, he's sitting in it with the door open. As he jumps out of his car to get in the carriage he leaves the door open. When the car is shown again the door is closed.
John and Jim are walking UGA (the dog) to Jim's home. They go into the workshop and UGA is not with them.
At around 59 minutes when John is in the flower shop, Mandy mentions petunias for a bouquet. Petunias are rarely used in floral arrangements. In addition, John smells the white poinsettia plant (twice actually) but this flower has no scent.
The end of the first day of the trial, the judge tells the jury to go home and not to talk to anybody and says they should report such contact the next morning. After this Sonny and John leave the courthouse and Sonny explains that he is going away for the weekend. As the trial is was not just one trial but four in total, there is no reason to assume that there is a conflict in timing.
When Jim sits down to start playing the organ at the Christmas party, you can tell that he not actually not playing. When they show the organ behind John, the dampers on the organ chest never move. It would be very difficult for an organist to control the volume of the pipes in the organ chest without the use of the dampers.
In both shots of when Chablis is about to testify the judge is noticeably trying not to laugh.
Though set in 1981-1982, there are 1990s-model cars visible When Kelso and Mandy go to the morgue.
During the Lady Chablis nightclub performance, the audience can be heard applauding when she is finished with the bit in which she teases the doctor and his wife. However, no one is applauding when the camera pans the audience.
Piano player's moments out of sync with music when John Kelso arrives.
After Sonny has told John the story about the Judge's son being murdered, he drives away and the cameraman is reflected in the window of the car.
As Minerva looks up from her Forsyth Park bench to see the plane coming in for a landing, it is headed straight toward downtown Savannah and the harbor. The airport there is actually located north of the city.
When John steps off the tour bus at Forsyth Park, he walks south through the park in the opposite direction of Mercer House, where he is shown in the next scene.
When telling Jim that he's having trouble getting people to talk to him, John calls Jim "Kevin".
(at around 2h 09 mins) In the courtroom the lawyer, Sonny, refers to his client as "Tim" not Jim.
In two separate scenes, when talking about the nurse bagging Billy's hands, Sonny calls the hospital where she works "Chandler," despite the actual name being "Candler."