Round 30 or so, on a low tech, militia only, hard difficulty start, I sent a spy to a non aligned zone and the next turn had vision of all of the non-aligned area of the map. The previously individual non-aligned zones have been coalesced to 1 big zone spanning most of the map.
It appears the cause is a major faction being overrun by non aligned forces (Chaudnon city). You can see the airbase asset is still decaying. The mega non-aligned zone has population from the city and more than 8 pages of assets in it.
The game is otherwise playable afterwards.

