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.
Suggested correction: Teachers often have to work the weekend to prepare for the school week.
Knowing Dorothy, she probably made the statement about having to work - to trick the others into being quiet. But, as the script goes.
Even as a long-term sub, she wouldn't have to be up early in the morning for work just because she might have papers to grade or a lesson to prepare.
I never believed this was a mistake. Bedtime Story aired in February 1987 and Dorothy was probably referring to her job at the museum that Blanche worked for. That episode (Joust Between Friends) aired two months earlier in December 1986, so it's possible she was still working there in the flashback (since it was never mentioned when/why she left).
I always thought that Dorothy was teaching drivers education, which was often on a weekend or after normal school hours. She complains a couple times about teaching drivers ed throughout the series.
Character mistake: Sophia tells Dorothy that lying is breaking a commandment, to which Dorothy corrects her by telling her that it's not a commandment. Actually, not lying is in fact a commandment. The biblical quote is "Thou shalt not bear false witness against thy neighbor." Whether it's an error on the part of the writers or an intentional mistake for Dorothy, it's still a mistake. (00:12:15)