Copied from another thread:
Also, special forces are making setting up satellite worlds very difficult. Even if you take a planet for yourself, if the special forces was on route to that planet or even merely routing through that planet, they will still try to go to it instead of trying to re-route around it (or change target planets). Thus, when setting up a satellite world, you can easily get 2000 special forces ships popping in even after taking the planet, sometimes even when there was nothing on that planet that special forces would want to defend.
Anyone else observe similar behavior?
Please make sure to differentiate special forces from threat fleet. I would expect threat fleet to do this sort of thing (attacking new, remote worlds), as they are geared for offense, not defense.
Generally, you can tell between the two by watching what happens after the command station is destroyed. If they leave, it is likely it is special forces. If they stick around, it is likely it is threat fleet.
You can tell for sure by checking debug mode though. (Bound to F3 by default, which among other things will add various debugging info when you hover over a ship, like their current AI "subroutine")