Can move through major civ turf WITHOUT Open Borders

I've noticed it in a few games, and just confirmed. It usually happens when one AI takes over another AI's cities, and I had an open borders pact with the cities' former owner. The game will let me move units through parts of their territory near the cities they conquered even without an Open Borders treaty.

Did this occur when the city is still in resistance?

Perhaps the tiles aren't "officially" transfered to the new civ until they gain control of the city.

This happened to me as well. After a war with Hiawatha he signed peace and gave me open borders. But his units were still in my territory although I did not give him open borders. After 30 turns the peace treaty ended but we both had still open borders which could not be cancelled. This was very annoying as he went through my territory to attack a liberated nation and I was going for diplomatic victory.

Are the cities in question puppeted? Or, were they annexed? It *shouldn't* make a difference in terms of gameplay logic, but there might be a coding reason for it that was overlooked. Just a thought.