The Sister - S4-E6
Continuity mistake: Marie comes over with a cake shaped like a cross. In almost all the scenes where the family is sitting at the table different pieces of cake are missing. In some of the camera angles there are no pieces of cake cut from the bottom yet when the cake is seen from other angles there are.
The Tenth Anniversary - S4-E16
Continuity mistake: In this episode, it is snowing outside but in "The Wedding Pt1" the date that they book for the reception is on the 17th of June.
Continuity mistake: Amy's brother was called Russel. In later episodes he is called Peter.
Continuity mistake: At the beginning of the scene where the three Barone kids are singing along to the Hackidu song with Robert on the couch, the scene opens with a picture of the house from the outside, and it is light and not raining at all. Then, when Ray comes in minutes later, it is suddenly dark and pouring rain.
Continuity mistake: This is a flashback episode of Robert's Divorce - they show that Joanne dumped him because she didn't like their life together but in another episode, Ray says that Joanne dumped him for a guy that he arrested.
Answer: War.
By whom?
Edwin Starr.