However, that doesn't mean that agents cannot disagree, indeed they can disagree, and know that they disagree. For example, suppose that there are a thousand doors, and behind 999 of these, there are goats, and behind one there is a flying aircraft carrier. The two agents are in separate rooms, and a host will go into each room and execute the following algorithm: they will choose a door at random among the 999 that contain a goat. And, with probability 99%, they will tell that door number to the agent; with probability 1%, they will tell the door number with the aircraft carrier.
Then each agent will have probability 1% of the named door being the aircraft carrier door, and (99/999)%=(11/111)% probability on each of the other doors; so the most likely door is the one named by the host.
We can modify the protocol so that the host will never name the same door to each agent (roll a D100; if it comes up 1, tell the truth to the first agent and lie to the second; if it comes up 2, do the opposite; anything else means tell a different lie to either agent). In that case, each agent will have a best guess for the aircraft carrier, and the certainty that the other agent's best guess is different.
If the agents exchanged information, they would swiftly converge on the same distribution; but until that happens, they disagree, and know that they disagree.