So, I may have accidentally let a character in the Shadow spec get a hold of a stealth field generator. He has the talent that makes it impossible to detect him or his Force use with the Force, and the stealth field makes it very hard to target him visually, and he has the Misdirect power to make it flat-out impossible for characters to detect a target of his choosing (like himself) if the stealth field is insufficient.
So how do you overcome this? Not that I want to build every enemy to be able to bypass his trick. . . the player has a solid, worthwhile build, and I want to reward him for playing it. But it's already become a bit problematic in one battle with a recurring nemesis, and I want to make sure that some fights are appropriately difficult, with the standard tricks not working as well and forcing the characters to improvise and really dig deep to pull out a victory (or to have a fight end up with everyone but the Shadow incapacitated, and the bad guy unaware of the Shadow's very existence).
I'm hesitant to add specific counter-abilities to certain NPCs, though I might be considering it for the ancient Sith Lord the players just popped from his carbonite can.