Character mistake: When all of the ladies are sharing Sophia's bed because there's been a cold snap and she has an electric blanket, Blanche mentions that her bed has never been so cold on a Saturday night. A few minutes later, Dorothy - upset that the other ladies are keeping her awake - states that she has to get up for work "very early in the morning." Dorothy is a substitute teacher, and would not have to be up for work early on a Sunday morning.
Character mistake: The number of years that Sal has been dead and the number of years that he and Sophia were married, constantly changes. In Season 3 Episode 5, Sophia says that she and Sal were married for 52 years. In other episodes, she says he's been dead anywhere from 22-30 years. If that's the case, given that Sophia is 80 at the start of the show, Sal would have died when she was about 50. Meaning that they would have had to be married since birth to be married over 50 years.
Character mistake: In the scene in the kitchen in which Rose says that Bob Hope could be her father, she tells Dorothy and Blanche that Gunter and Alma Nylund are her adoptive parents. Nylund, however, was her husband Charlie's last name, making it Rose's married name and not her maiden name. Nylund was not her adoptive parents' name.
Character mistake: In her first appearance, Kirsten liked Dorothy, Sophia and Blanche and said that after her visit she now understands why Rose loves living with them. In her second appearance, she heavily dislikes the three women and states that she never understood why Rose preferred living with them over moving in with her.