Continuity mistake: When Derek's uncle arrives during his interrogation, the badge and pen in front of Jack change position entirely. When the original camera angle is used again, the objects are exactly where they first appeared. (00:28:05 - 00:29:20)
Continuity mistake: As Miss Fisher explains how to eat asparagi, the dark haired girl has her fingers on the veggie in a different position in every shot. (00:02:00)
Continuity mistake: When Jack and Hugh arrive during Miss Fisher's judo lesson with the girls, the two outraged ladies walk out of the room twice. (00:15:55)
Answer: Louisa's watch was broken during the struggle to get away from her attacker.
Bishop73