It might be a player-only bug, so you could not test it by attacking an AI yourself. For my abandoned game I certainly did not have Militia units for many turns, even if a city didn't get attacked at all in between.
I stopped because there was no way to win with the militia and reload-finishes-AI-buildings bugs combined, even though I was clearly going to win, without those bugs :/ It's a great game, but a few heavy bugs can ruin it. Still not giving up on it though. 
I will try to produce a savegame, but I might have overwritten all of them...