... The F, says the person is reincarnated, but that's the only indication of it. -- MC acts as if he's from that world, with no prior knowledge. If so, how would he know he's reincarnated?
IT'd have been better to just skip that part, imo, because it has no baring on the story. Or it could have been revealed later, by having him get a headache, or something, and 'remembering' about his past life. -- Though, I guess it could just be a translation error, or a way for people to self-insert easier *shrugs*.