Thanks for the reply Frostion. Yea that makes sense. I remember having to do that when I wanted the same unit to have different maxbuilt for players.
However one of the techs I have is a new "shipyards". So it's adding and/or subtracting units to players production. Everybody has their own production now, so I'm not quite sure why they'd all be affected. I must be using a condition that somehow is sensed by everybody's trigger. I was pretty sure everything was player specific named though. Perhaps a fresh look will allow me to find it.
So on your 2nd example, I don't quite follow. Wouldn't all Heavy-Cruisers receive the bonus ? Do you have to have a playerAttachment of some sort as well ?