Are the bots different masses? Maybe it has to do with inertia some how. Try getting the bots to be the same mass and see if that makes a difference.
Does something aside from body, energy or shell have an effect on mass?
*edit - one sec. playing with masses
This behavior seems to continue with matching masses. im going to post a sim in a moment
This is very strange. Before I saved the sim, it continued, but when I loaded it again it stopped Oo
How often does it update mass?