the reason behind no AI naval invasions?

[anweRU]

This is a METW2 discussion, but after 1.2/1.3, essentially all Med factions want to capture Ajaccio & Cagliari. Everyone from the Pope to the Egyptians will attack those two islands, and any faction hapless enough to hold them.

Back to the region trade topic:
Much to my surprise, I saw Montreal had become an Iriquois territory in my current Sweden game (stopped my Dutch campaign due to a CTD just a few turns away from victory, bugger).
When I looked again, Michigan had become French. I looked at the diplomacy screen, the two are at peace. So this is my second AI-AI property swap so far in 5-6 campaigns. Happened around 1705 too, so these things can happen any time.