The bomb expert mentions how intricate the 1 October bomb was, but bomb was easily removed without ask the hassle with the bomb Budd was wearing.
Commander Sampson is wearing the wrong insignia. The crown, pip and tipstaff wreath she is seen wearing on her shoulders is the insignia of the Commisioner. A Commander would wear a tipstaff wreath alone, with no crown or pip over it.
When David Budd was disarming the suicide bomb that he was wearing, his actions were watched from a safe distance by explosives expert Daniel Chung via a robot that was equipped with a GoPro Hero 4 Silver Edition camera. However the camera's status display screen was blank, showing that the camera was turned off.
During the park scene as everyone is communicating via radio, they all stop releasing the push-to-talk buttons.
In the whole time David is isolated in the open area between buildings by the Special Response police and is in active dialogue with his former fellow investigators, no one asks about the blood on his face. There is no mention in the dialogue from David that he was beaten up, knocked unconscious, and forced to wear the bomb vest.
That the blank rounds would be left with fingerprints by either organized crime or security services is an absurdity given the phenomenal complexity of the conspiracy portrayed in this story.
The mastermind bomber provides an extensive confession without any plot motivation to do so beyond interrogators yelling angrily at them. This is an obvious device to reveal the whodunit at the end like a Midsommer Murder, but it makes little sense in the context.
The character claims that the suicide bomb vest has a "dead man switch" which would detonate if he were shot. But later, he is cutting off the tape that had been holding his finger down on the dead man switch. That tape would have prevented the switch from releasing and detonating. Furthermore, he was unconscious when the vest was donned, so a dead man switch would have already detonated before he had even come to.