This is now the 3rd big patch and the Devs keep overlooking the issue with the vasari AI when using custom maps. If the starting location doesnt have planets that they can colonize within the first tier of Empire tree such as Volcano, Artic, Primordial, and crystaline within the next gravity well, the AI just stays in the home planet gravity well and builds until they hit thier military cap of tier 2. 

I have confirmed this on many custom maps. I first noticed, when after a game was done, the report showed that the vasari AI players only had 1 planet the first 2 hours of gameplay (until they were snuffed out by another AI)