I think it's broken worse than that. A false belief with certainty will allow for something like the explosion principle.

http://en.wikipedia.org/wiki/Principle_of_explosion

As implications of magic collide with observations indicating an ordinary wire, the AI may infer things that are insanely skewed. Where in the belief network these collisions happen could depend on the particulars of the algorithm involved and the shape of the belief network, it would probably be very unpredictable.