Continuity mistake: Optimus and the car Tessa is trapped in are caught in a net and are pulled up to Lockdown's ship. Cade then jumps and grabs onto the net whilst it is being raised. There is a brief moment where Optimus is not visible inside the from the net, before being visible again in the next shot. The CG artists likely forgot to add Optimus into the shot during post-production. (01:22:35)
Revealing mistake: When Tessa and Shane are trying to free Optimus from being impaled to the wall after he is stabbed with his sword, there is a shot of Tessa running towards Optimus after she grabs the hook belonging to the tow truck. In the background of the shot, the Willis Tower, also known as the Sears Tower, can be seen in the far background. The buildings surrounding the tower can also be seen as well. The Willis Tower is located in Chicago, but the scene is set in Hong Kong. The scene was likely filmed in Chicago. (02:32:40)
Other mistake: When Cade is fighting Savoy, Cade jams his thumb deep into Savoy's right eye socket. A moment later Savoy is seen with no right eye injury.
Other mistake: During the introduction of Attinger, he is holding cards of the Autobots explaining what happened to them. One such card is of Ironhide, listed as last seen in Chicago. Ironhide was killed in Washington DC at NEST headquarters by Sentinel Prime in Transformers: Dark of the Moon. He didn't even participate in the Chicago battle.
Factual error: In the film, all the Hong Kong cars' steering wheels are on the left, even the local taxis. Hong Kong drives on the left side of the road, meaning the steering wheel is on the right side, just like in the UK.
Factual error: Darcy tells Joshua Joyce about the meteorite that caused the dinosaurs to become extinct; she mentions that the piece of metal in question has been carbon dated to 65,000,000 BC. Carbon dating is limited to around 40,000 years. For longer time periods potassium-argon dating or other techniques are used. Additionally, carbon dating is used for life forms, not for metal. (00:58:45)
Continuity mistake: Just after Lockdown stabs Optimus in the chest with his own sword, Cade runs closer and shoots at Lockdown. He then hides behind some bricks. In that shot, the bricks are a broken wall that is two separate pieces. Then it cuts to a different shot as Lockdown returns fire at Cade, and now the wall is one piece. A guy also suddenly appears in the shot next to the wall and right where the explosion happens where Lockdown shot the wall. Originally, this man was one of several extras portraying the silo factory workers wearing hard hats, who were running and hiding, but Michael Bay wanted this silo scene to be about just the main cast, so the scene was trimmed and the extras were cut, but this shot slipped through. Some footage can be seen on Blu-ray special features. (02:30:55)
Continuity mistake: When Optimus Prime and Galvatron first fight, after Lockdown comes for Optimus, Tessa hides in the abandoned car. Between shots, the car's door opens and closes.
Visible crew/equipment: When Lucas parks his Mini Cooper next to the old theatre and steps out, you can see a crew member's reflection in the opened car door.
Continuity mistake: In the scene where Optimus frees the "Legendary Warriors", aka Dinobots, they walk into the canyon area and Optimus addresses them and asks for their help. It appears there are 3, maybe 4 large robots. When Grimlock screams and starts to fight Optimus, the others disappear. They continue to fight, showing from wide angles, and the others are still nowhere to be seen. Grimlock then transforms and charges at Optimus, with nothing behind him or between the two. When Optimus knocks him to the ground, it shows the angle that he falls to the ground in slow motion, and the other warriors appear in the area that Grimlock just ran through.
Revealing mistake: When Galvatron is firing rockets on the Autobots, a flatbed truck swerves into the back of an RV causing it to flip over and explode. There is no driver in the RV. (01:17:40)
Continuity mistake: In the scene where the Autobots are escaping from the KSI building, closely pursued by Galvatron and Stinger, the satellite tracker used by Joshua to track them, using an orange false image view, indicates they are driving on a freeway leaving the city. This is backed up by a swooping shot showing the same. However a second or two later and they are in the middle of an open countryside, not a building in sight (there are many 360 degree camera sweeps), a few bridges and other cars, but also old concrete banked curves. This is on a test track which for some reason they didn't CGI to make it fit with the supposed scenery the satellite indicated they were near.
Continuity mistake: When Bumblebee and Drift reach KSI headquarters a Rolls Royce is in the shot. In the next shot when Bumblebee is transforming the Rolls Royce is far away from Bumblebee. In the next shot when Bumblebee is crashed through KSI headquarters there is no Rolls Royce parked out front.
Revealing mistake: When Bumblebee is transporting Joshua, his face is cut from another shot and placed on the one of Bee driving. This is obvious by the incorrect lighting on his face and lack of reaction to his surroundings.
Visible crew/equipment: After Optimus stabs Lockdown and slices him in half with his sword, it cuts to a shot of Tessa witnessing it, and Shane getting out of the tow truck. When the camera pans towards Shane, he shouts "Yeah" and the reflection of a boom mic can be seen on the wing mirror of the tow truck just before the shot cuts. (02:33:20)
Revealing mistake: When Bumblebee drives up the KSI building, he swerves the car around to face the building and let Tessa and Shane out. The tyre marks are visible on the ground before he swerves the car, most likely from a previous take. (01:12:10)
Continuity mistake: During the scene in which Tessa is hanging onto the wires suspended above the skyscraper, Lockdown's dogs start crawling on the wires behind her. The dogs then disappear in the next closeup of Tessa, only to reappear in the next shot. (01:39:10)
Factual error: The elevator Cade leaves because there's "too much weight" shows in the next scene a weight limit of 680kg. Even if the four passengers weighed 90kg each (a total of 360kg) it would mean the seed weighed more than 320kg (over 700lb), which would mean that Joyce would never be able to carry it alone as he did several times.
Continuity mistake: When Lock Down is giving the seed to the CIA the scratch on his chest is top left to bottom right, while in the rest of the movie it is top right to bottom left. (01:27:35)
Visible crew/equipment: During the finale battle with Lockdown when Shane is driving the truck, you can see the shadow from the filming Go pro on the wheel of the truck. (02:32:35)
Answer: Optimus was being dramatic when he said it contained their memories. Transformers don't carry their memories in their spark any more than humans carry theirs in their soul.
MasterOfAll