Factual error: Bill wears four medal ribbons, in order: Diamond Jubilee Medal (awarded to all people with five years' service in a British uniformed service in 2012), Golden Jubilee Medal (the same in 2002), Queen's Police Medal (a very prestigious award, a handful of which are awarded every year to long-serving police officers for exceptional service) and Police Long Service and Good Conduct Medal (awarded for 20 years' unblemished service in the British police). Not only are these in the wrong order (it should be QPM, Golden Jubilee, Diamond Jubilee, LS&GCM), but he's not entitled to any of them! He's an American who hasn't previously served in the British police. A chief constable's uniform doesn't just come with medal ribbons for the look of it; only those that have been earned may be worn.
Factual error: Alice and Kate's little reunion underwater is disrupted by policemen that fire at them, and one of the shots reaches the transport truck, ignites it and makes it explode. The scene is baffling; forgetting the complete disregard for fellow policemen in the vehicle, how would bullets have enough strength to penetrate into an armored truck deep underwater, reach a critical weak point from that angle (the truck is upright, they should be barely get to shoot the roof of it) and still underwater cause inside the completely immersed vehicle a spark that would ignite fuel and make the whole truck explode? (00:31:45)
Episode #1.7 - S1-E7
Factual error: When Marie is talking with her therapist, she talks about having just gone to see Zombieland. Given that the scene takes place in 2008 and Zombieland wasn't released in the US until October 2009, this simply is not possible.
Suggested correction: The series starts in 2008, but it's 3 years later. At the beginning, RoseMarie says Curtis was born February 3, 1981 and is 30 years old.
The therapy scenes are in 2008. It's only when the photographs of Marie are discovered that we see Marie 3 years later, in episode 8.
Continuity mistake: In s02e09, "Enter the Dragon", when Father Jun shoots the second Irishman, he's holding the pistol with both hands. But in the next shot, he's back to holding it with one hand.
What They Saw in Southie High - S1-E2
Other mistake: Agent Rohr asks who the cold case is related to. A dossier is given to him and the front cover contains a photograph and the name "Kanicki, K". Agent Rohr says "Kelly Kanicki" but there was no indication of the full name, just the initial. (00:08:30 - 00:09:00)
Plot hole: The captain's wife tells him that she's taking his daughter with her, not giving him a chance to even say goodbye. During the episode it turns out that she's angry because he missed lunch with them, and when the Metal Wu texts the boss, it also turns out that all this just happens at 1:11 AM! It does not make much sense: she waited over 12 hours to complain to her husband, and she's driving her kid in the middle of the night.
Factual error: Almost none of the senior police officers wear the correct medal ribbons. Brian Moore and Pat Geenty wear the Order of the British Empire, which neither had. Geenty wears the General Service Medal, for military service in Northern Ireland, although he was never in the armed forces. Moore does not wear the Queen's Police Medal, which he was awarded in 2009. Both wear the Diamond Jubilee Medal in 2011, although it was not awarded until 2012. Andy Parker wears an unidentified ribbon (possibly intended to be the Queen's Police Medal, which he was awarded in 2010, but looking nothing like it) and the Golden Jubilee Medal, but does not wear the Diamond Jubilee Medal or the Police Long Service and Good Conduct Medal to which he was also entitled. Mike Veale and Ray Hayward wear no medal ribbons at all, although both would be entitled to the Golden Jubilee Medal and Police Long Service and Good Conduct Medal (and Veale also to the Diamond Jubilee Medal after 2012).
Continuity mistake: When Nick's mom tells him to show Gypsy around she takes the cigarette away from her lips. A shot later it's back in.