If I remember correctly, in the last dev stream, Paul talked briefly about this, but I just want to make sure.
So, it has already happened to me countless times that the AI colonizes a planet in my zone of control (ZOC), and sometimes even on systems which I already have a colony on. Of course, culture flip means that they will lose the colony to me in a few turns. Souldn't the AI know that it shouldn't be doing that and wasting its colony ships on it? Besides, that is a problem from the roleplaying point of view: what if I want all of my colonies to be populated by my own species? Because, when a colony flips, it is basically only changing its allegiance, but the species which live there are still the same as before.
What I propose is that the chances for the AI to settle within your ZOC should be lower, specially if the system already has a colony of yours. And if they colonize it, then they should build some starbases around, to protect their colony from flipping.