I don't know how it happened, but i can't place any structure myself, each time i try to build something, the CPU insists on placing it for me, most of the time where i don't want it of course.
In my current game, i have two full upgrade orkulus in my frontier "systems", but i can't place correctly my jump interdictors so the enemy doesn't just pass by and jump to my inner systems 
Anyone knows how i can disable this feature/bug. I only found an option to disable auto placement for extractors, it's the only auto-place i'd like to keep.