Maybe this is just the way it's intended and not a bug. I've been playing shadow/assassin in the 55 HMs but recently started getting my op/scoundrels playing in them, and I noticed something. In Hammer Station, the turrets are cc'able. Athiss has no turrets. Cademimu has the mounted ones which are never cc'able. Mando Raiders, though, is the problem. It has a bunch of normal turrets, not unlike Hammer, but you can't cc them. Now, my guess is that because the ones with the boss can't be cc'ed, none of them can, but it's annoying and inconsistent.