Character mistake: The Sheriff calls for Drayton Sawyer to bring out his son Jed (Leather Face) in the movie's opening scene. But it's long been established that they're brothers.
Suggested correction: This is meant to be a direct sequel to the original film, and ignores the other sequels. And if memory serves correctly, the first movie never made any mention of them being brothers. (I just checked and the Texas Chainsaw fandom Wiki backs this up - the original film makes no reference to them being brothers.) So therefore, it is not a mistake if this movie re-writes him as being Leatherface's father.
Character mistake: Early in the film we are repeatedly shown the alien character flirting happily with various men, relaxed, confident, even socially forward, in fact often more articulate and socially at ease than the various Glaswegians she encounters. Yet later on, inexplicably, all this social nous mysteriously disappears and she is completely baffled and blindsided by the simplest of social interactions, almost a mute. Since the film has virtually no plot it's hard to see why this jarring turnaround should be so.
Character mistake: In the scene discussing the provenance of the mirror, the girl stated that Sherman marched to the sea in 1865. It was actually 1864.
Character mistake: When Joan is searching the web looking for information on what monkeys eat, there is a section on the screen that reads "The diet of monkeys varies form fruits, leaves." Obviously the correct word for this sentence should be "from" not "form." (00:36:21)