The Case of the Borrowed Baby - S5-E26
Continuity mistake: Mason takes the medallion back from the matriarch as he leaves her home. A little later the old lady shows up at Della's and shows the medallion to Della.
The Case of the Borrowed Baby - S5-E26
Continuity mistake: As Della burps the baby she has a towel over her shoulder one instant; in the next scene the towel is missing.