I agree it appears most likely Thompson is making it up himself. So moving on to the question of motive, I'm thinking we should check into who his editor is. It seems to me that if Thompson only does this once or twice, it could be he's a "lone nut" who is venting a personal political grudge, or gets his kicks from hoodwinking the public, or something like that. But if he keeps doing it repeatedly, as appears the case--we've now found at least three examples, I'd be willing to bet there's more out there--I start to wonder why his editor's letting him get away with it.
He may or may not be in this alone, but he certainly has been lying for a very long time and caught in his own lies, many times over.