Sorry if this bug has already been noted, but I encountered something funny that required a reload. One of the AI's cities bordered the Pit of Despair. I took an army into this city's territory, and got the AI prompt telling me to stop trespassing. I clicked on the option to politely leave rather than to start a war. My army was then ejected from the AI's territory only to be relocated in the inner section of the Pit of Despair, at the point where you can summon Samarra. This would have been fine, except it was only early in the game and I had not yet initiated the Master Quest (such as sought out the darkling shaman). So the first gate was closed. My army was trapped between the two gates. It would have been a great shortcut for completing the Master Quest, except my army was too puny to take on Samarra.
I think it'd be better if units could not be placed in that inner gated area, or at least not until the first gate has been opened.