AMIDST isn't perfect. I've had at least a few false positives for villages before, too. But most of the time it's pretty accurate. Just find the next closest one to your location, and go look there for it, there'll probably be one there.
Yeah, AMIDST can report village locations that technically should be there but the game doesnt create them; not sure why. I had an example of this when i started out in my current world; AMIDST showed there were five villages in a kinda of line where my minecart line was heading, thought it would be a great little trading area i'd have, but when i got there only two of the villages were actually created.