Revealing mistake: In the scene where Sarah crashes into the agent's buggy, you see they have been replaced with dummies. When the car first hits, you see one of the dummies fall out, but they are both seated in the next shot. Also you see that it is not Sarah driving but a man. (00:36:50)
Other mistake: The psychologist shows Michael a photo of his family with his Mom, Dad, Michael and Lincoln but Michael never actually met his father when he was young.
Revealing mistake: When Sara crashes into the ATV to save Michael, you can see that the people on the ATV are switched out with crash-dummies.
Answer: Because of coincidence.