Audio problem: Anthony Hopkins is in his car with Cogman, discussing Pangea the super continent over the phone with John Turturro. There are two instances in this scene in which Anthony Hopkins' voice has been dubbed over by a different actor that does not sound like him. Anthony Hopkins first says "That's Pangea. The super continent." The scene then flashes back to the round table and the dubbed voice attempting to sound like Hopkins says "It's the same shape on the round table." The dubbed voice is heard again when he says "Genius", before reverting back to Anthony Hopkins immediately after when he says "Stonehenge."
Continuity mistake: When Anthony Hopkins is on the phone with John Turturro, an Autobot approaches the phone booth he is standing at to talk to him, and stands in front of the phone. A few seconds later, the Autobot starts to walk away by walking forwards. The shot cuts to Turturro telling the Autobot he'll be five minutes, and it has suddenly vanished from in front of the phone booth.
Continuity mistake: When Bumblebee is driving through London there are suddenly a couple of shots from some American town, you can tell from the different street name sign styles. (01:28:35)
Continuity mistake: During the junkyard fight when they show Sqweeks leaving his decepticon arm is missing, only to show up again when Megatron finds him.
Factual error: The finale takes place at Stonehenge. It is shown surrounded by woods, not in an open plain as it really is. It is also missing a security fence, dyke, a main road and visitors' car park. There are also hills, whereas Salisbury Plain is quite flat.
Other mistake: Opening battle: 2 horsemen are hit by fireball mortars and fall from their horses. Moments later, the same horsemen are hit by arrows and fall again. It's the same footage - reused. (00:00:35 - 00:05:40)
Character mistake: Namibia was said to be in West Africa. Namibia is in Southern Africa.
Continuity mistake: When Vivian arrives with Hotrod at Lord Burton's castle, she is wearing black tennis shoes. When she is inside examining all the artifacts, she has black heels. She was not carrying any shoes, and even if they were in Hotrod's trunk, they would have been crushed during the transformation.
Continuity mistake: When John Turturro answers the phone call from Anthony Hopkins, there is visibly nothing around the phone booth. Later into the phone call, an Autobot has suddenly appeared in front of the phone booth, asking for Turturro. No way could the Autobot have approached the phone booth in complete silence. The footsteps of it would have been heard.
Continuity mistake: When Anthony Hopkins is talking with the Prime Minister, he takes out a clock Autobot which he threatens to use on the guards. He is still holding the clock Autobot in his hands when he turns back to talk with the Prime Minister, but in the next shot, it has suddenly disappeared from his hand.