Revealing mistake: When Charles shows the picture of the horse and says "look what you get when you search for 'Charles Boyle medal of valor'" he's typed "peanut butter the horse" into his phone.
Revealing mistake: During the attack on the Range Rover in Shanghai, China, none of the passers-by react to the gunfire in any way. An automatic weapon's unloaded into the windshield, then a window smashed with a pistol fired through it, but people on both sides of the street don't even look up, they just keep on shopping. The attack was clearly composited into generic footage of a city street. (00:00:50)
Episode #1.4 - S1-E4
Revealing mistake: The tabloid story with the plight of the Latimers just came out, and various characters are looking at it. In the bit when David Tennant tosses on the desk his copy of the Herald, the second paragraph of the second column goes "Sitting in the family home, surrounded by pictures and mementos of Danny" etc. It is the same text that was at the very beginning of the article when the store owner was looking at it. The newspaper is a prop with the same text in a loop. (00:35:00 - 00:36:30)
Revealing mistake: Every phone call in the show, the phones never show the correct screen. Either it is glitching behind their ears or it's the home screen.