It isn't, but the rules are weird and with the multiple factions in multiple states that they introduced a while back it might as well be.system state BLIGHT, imperial Faction HGE: Civil Unrest, spawns imperial shielding.
I give up, it is just random.
All I do nowadays is load up on whatever G5 stuff I can find, and trade for what I need. It's easy to fill up on the more common G5 stuff. I got Proto Radiolic Alloys up the wazoo.