The principle is now clear, but it's unclear why it was introduced. I wouldn't want to start another flame war, but where did this new feature come from, which, as I understand it, is now mandatory?
I hope the mirror map tournament will be played on version 1.34 without the obligation to play on version 1.35.

Then, in order to prevent the game from turning into a stalemate of running around in circles when there is no control, because in mirror maps the road network is not tree-like, as in standard templates, but cyclic.

This should not have a significant impact on the game strategy, because on h3dm1 there are 10 cities per plane (on Diamond there are 12), so control, purely in theory, usually exists somewhere. Knowing that control definitely exists doesn't really help - building 3-4 GM5s is only possible on XL+U, on mirror maps the game ends earlier.