AI and colonization

[Rexxx]

During the Last days I ran several games with all AIs (standard, TDM and my own) under player control but with "full AI on" just to watch the colonization minister (and his colleagues) working. Well, he did a hell of a job. Is it only my impression or he is ordered to never set up a colony in a system which is claimed by an ally?

Sometimes in midgame - when there is peace throughout the quadrant - the whole colonization business comes to a halt. With no free or hostile systems in range, the colonizers full of happy wannabe-colonists are orbiting their homeworlds for years. When new colonization technology becomes available the AIs begin to fill up their own systems but again never one of their allies.
Can anybody confirm this? Is there something I can do against it?

I like to have my AIs peaceful but not to this point of doing absolutely nothing.