Continuity mistake: When Mammy Watkins first hands the letters over to Blanche, the ribbons holding them together are knotted but the knot is on the bottom of the pile, and the strands are quite long. When Blanche reaches for them, the knot is on the top, it is now tied in a bow, and the strands are much shorter and neater.
Continuity mistake: As the show begins, an outside shot of the house shows that it is night. Then it cuts to the scene of Blanche and Sophia playing Chess in the kitchen - when Blanche is complaining about Sophia's "do-overs" you can see outside the kitchen window and it is daytime. After Rose walks in about 30 seconds later, you can see that it is night again.
Continuity mistake: In the scene where Stan stops by the house to have Dorothy help him tie the bow tie of his tuxedo, the undone tie is hung around his neck. After Dorothy finishes tying the bow tie and Stan proceeds to leave, she stops him to tell him to return in an hour. He excitedly turns around towards her, at which point we can see that the bow tie is now a clip-on. (00:18:55 - 00:20:55)
Character mistake: Throughout much of the show, except for a few boyfriends Dorothy has had difficulties finding men to go out with her. Much of the show's humor is based around Dorothy looking unattractive and having no dates, and Sophia often desperately tried to arrange a rendezvous for her daughter. Nevertheless, in this episode, Sophia had no problem at all to find a whole bunch of men that are more than willing to go out with her, and according to the suggestive gestures Dorothy mentions, some of them apparently had a strong sexual interest in her after having seen her. They even offered their services to a cheaper price just to go out with her. Why is it so easy for Sophia to find that many men that eager to meet her daughter all of a sudden?