Revealing mistake: When Lizzie awakens on the morning that Edith gets released, Edith doesn't respond and Lizzie goes to her bed to "mourn" the passing of her friend. Except that Edith is still breathing.
Continuity mistake: When Karen first moves in with Angela Jeffries (lesbian lawyer) after leaving the old ladies' ward, Angela discloses to Karen that she's a lesbian. However, a few episodes later when Karen returns from a date with Dr. Greg, Angela discloses to her again that she's a lesbian, and Karen acts all surprised and disappointed.
Visible crew/equipment: Shadows of the boom, crew, and cameras can be seen moving about in overhead shadows during varied scenes.
Deliberate mistake: After MacNelly enters the ladies room to confront the red haired lady, she shoots the woman in the chest, but there's no gunshot or bullet hole or blood anywhere. But the red haired lady dramatically collapses to the floor. Then during a closeup, glances upward at MacNelly, and then her head droops downward.
Other mistake: When Lizzie, Bea, and Lynn visit Dr. Greg in his office, Lizzie visually 'sneaks' a pack of meds from the open tray across from Dr. Greg. But he somehow doesn't see this in plain sight, while talking with Bea.
Revealing mistake: For a prison governor/warden, Mrs. Davidson (Erica) would presumably earn a modest upper middle class salary. Yet here she is on the phone, in the foyer of her home, wearing an elaborate house dress, surrounded by very stellar furnishings. But then she answers a knock at the door, and opens it to reveal a very ugly vertical striped wall mere feet behind her visitor. Obviously indicating that she either lives in a dim-tenant or low-scale apartment, or this scene was shot in-studio.