Blood Bath - S4-E8
Revealing mistake: Elsa's legs are supposed to be wooden prosthetics, but when she walks away from Ethel, who's holding a gun at her, it cuts to a shot of Jessica's calves which bend slightly as she walks. (00:00:14)
Revealing mistake: When Elsa is waiting in the lobby, she's wearing a dress which shows her normal, not wooden legs. It's very apparent when she is crying on the floor.
Revealing mistake: When Dandy shoots Penny through the sheet, the second sheet flies out as it's hit with blood. But the sheet he shot through has no hole in it.
Answer: Moira's ghost form is unique because of the way she was treated when she was alive. To people who do not sexualize her and truly understand and view her for who she really (namely women), she is seen as an older woman. To people who objectify and don't care to see the truth (namely men), they see the young seductive Moria. It's a strong directorial choice to eventually show how Ben Harmen comes to terms with the truth of the house and himself.