Hi guys, I'm a bit new here and I'm with W-Y Corp.
I'd just like to say that I think it's fair to believe that the smoke trail would be noticeable despite cloaking. I've done a lot of Sci Fi Rp's and the cloaking devices are usually just optical cameras that stud the surface of the subject that it's meant to be cloaking (IE a human, alien, ship, or whatever) and then project the surrounding images across the surface of the subject. That to me, says that the smoke trail wouldn't be cloaked.
Now I don't know if the Preds have some higher type of cloaking device that makes this possible, but that's just my understanding of that sort of tech.