Immediately after Lloyd Hansen (Chris Evans) bloodies Fitzroy's (Billy Bob Thornton) nose by punching him in the face, the next cut to Fitzroy shows no blood. It's back again when he's hustled into Hansen's waiting vehicle.
When fleeing the scene in the red vehicle at 1:19:04 the windshield is not shattered, but is when vehicle comes around the corner at 1:19:07.
When they are stripping Sierra four of identifiable items at time 13:25, his left hand is palm down, they remove the watch from his left arm, and the hand falls back with thumb upwards, palm exposed,they then complete removing items and the left hand remains thumb up.
In the next overhead shot clearly shows Sierra four still has a watch on his left arm and the hand is palm down.
When Lloyd brings in Fitzroy to Croatia and has an argument with Suzanne, he aggressively clears off the coffee table. After that, it's immediately visible that there are some items remain on the table.
In the final fight scene at the fountain between Lloyd and Six, Lloyd took his shoes off after they first tangled, when he is lying dead in the fountain, his shoes are back on.
When Six is at Margaret's house in Prague, a team is shooting at the house. The house is on an upper floor, while the team shoots from the street, at ground level. Yet, the bullets hit the apartment from up to down, the opposite direction of what it should be.
Lloyd fires a single use flare gun multiple times without exchanging the flare round.
Orange smoke signal flares typically use strontium nitrate which provides the color, and potassium perchlorate to oxidize the strontium and cause it burn. Both the smoke and the the potassium chlorate are highly toxic, caustic and produce enormous heat all of which would be be crippling to anyone in an aircraft or other enclosed space. And flares do not ignite immediately; there is a delay of a few seconds for the user to throw them a good distance away.
The tram starts moving with all doors opened. This would be prevented by its security systems. Also, there is no driver in the driver's seat.
In the battle in Prague, the tram sometimes drives on the left and sometimes on the right track, which is not possible. Trams in Czech Republic drive exclusively on the right track.
In the final showdown between Six and Lloyd, Lloyd sits down and removes his shoes. As the fight moves to the water, His shoes are on.
When leaving Bangkok, Six takes a tuk tuk for Chiang Mai. Chiang Mai is located 683 km north of Bangkok. There is no way he could cover this distance in such a short time to the extraction point in an overnight ride.
The electric cables above the tram conveniently disappear when Six stands up on the roof.
There is a 16 year old gap in the narrative and yet Six does not seem to have aged at all.
Four's head should drop down when he dies. Instead it stands up against a pole.
Obvious CGI when Six and his "niece" jumped in the water.
When running into the apartment building in Prague, there's an explosion and the police are aiming their guns at Six to arrest him. It's the same as arresting someone for being run over by a car.
When Six (Gosling) rushes Claire (Butters) to the hospital, they drive a car that doesn't exist yet. The scene takes place in 2019, since the movie started in 2003, jumps 18 years ahead, then backs 2 years in this scene. The Audi E-Tron GT driven was not available until 2021.
When Dani and Six are driving through Vienna, police cars are driving past them. The audio of the sirens added in post are different to the unique sirens of Austrian police cars.
When they show the various teams from around the world mobilizing they show one scene from Sydney (at 32m50s) that is obviously a composite shot with Sydney's most well known landmarks, since there are no airfields anywhere near Sydney Harbour (the closest, Sydney International Airport, is on Botany Bay, 10km to the south).
While Six is trying to GPS the pacemaker in the hospital, he tells Miranda there is no "caps lock", so he needs to "ctrl+shift". To make an upper-case letter without caps lock, you would only need to press the shift key, not control.
The French mercenary says "Charles Trois" (Charles Three, pronounced "Shahrl Troah" in French). The international alphabet does not translate in French so he should have said "Charlie Trois".
The French mercenaries speak French over the radio but are part of an international team. They should use English to be understood by everyone.