Revealing mistake: When the arrow hits Brackenreid, a blood patch appears instantly around the wound. In reality, the arrow itself would clog the bleeding for seconds at least.
The Ministry of Virtue - S14-E6
Continuity mistake: Around the middle of the episode, Hart and Carmichael walk down a street with ice cream cones in their hands. When they stop for a brief face to face discussion, the ice cream in the man's hand keep changing from full portion to half-eaten and vice versa as the camera perspective switches back and forth.