The Vasari rebel titan's ability for anti matter at rank 2 gives 0.2 regen, at rank 3 it states it gives 0.0 regen, and at rank 4 it says 0.4 regen. I have no idea if it was actually giving back anti matter. (I totally almost called it Mana.)
When making a map via map creator, if you use more than one star and set orbit radius to anything but farthest left, no planets or suns are visible on the screen. They don't show up at all. I moved the slider to the left and went to preview and they'd appear, marked with solar systems when fully zoomed out, but with the orbit radius anywhere else, there was nothing, just a black screen full of stars. Also, occasionally I would not get my starter units to show on screen, and on two occasions there was nothing at all. No units, stars, planets, nothing.
Before researching the Vasari rebel ability to allow star bases to phase jump, you can have 4 star bases active on a star, with all 4 being active. After research, 3 of them disable, this seems counter productive to the point of being able to build multiple star bases at a star, and penalizes you for learning one of the techs.
Also, passives on star bases are not disabled when there are more than one base at a planet. I had tested this via building 30-40 star bases and giving them all civilian pods and trade ports, both of which stayed active. i did not think to test the bombardment talent with this as well, as you could just have two planets, build a base, tech it, send it over and have 100% of your income from bases and only have two planets to your name. If the base is disabled, it should also disable the passives as well. If the bombardment talent also worked you'd never be able to kill off all of the bases, even if they were only teched 2/3 weapons and 3/4 armor. One would die, another would replace it.