Or, I guess I should say the anti-cloak abilities are broken. The final battle with the dreadnought is very similar to that in Khitomer Accord. However, the abilities that normally disable cloak do not work in this mission. Charged particle burst does not disable her cloak (and I run version 3, fully specced into it on my sci toon.). Nor does eject warp plasma (again version 3 on my eng toon). I have not tried gravity well or tractor beam yet.
They did have patch notes about changing tractor beam's effectiveness on the Scimitar, it might have affected the other abilities too.
I think its really annoying and stupid, honestly, because cloak detection/revealing is so useless in PVE, that it would be nice for it to come into its own in these Scimitar fights. If it makes it too easy, then good! Lots of other powers make other fights super easy.
You can't stop her from cloaking. The only way to "stop" her is to have the rommie battleships ability to fire a stream of overloaded plasma balls at her as she cloaks...it makes her targetable for oh like 5 seconds (not kidding). Outside of that, just watch where the other plasma balls track to to know where she went. GL!
The Scimitar is now allowed to cloak while tractor beamed.
No mention of charged burst or anything else not decloaking a Scimitar. It used to work just fine and having just finished KA, being right on top of Donatra dumping warp plasma and using CPB when she went to cloak, it did not work even once.
If it isn't in the patch notes, I consider it a bug.
I know that CPB USED to bring her out of cloak. And, furthermore, it SHOULD bring her out of cloak by design. Her constant cloaking is one of the biggest gripes about how KA is unnecessarily long and a time sink. You used to be able to counter this with in-game skills like CPB, and this is what CPB is DESIGNED to do. If this is no longer the case, then Cryptic should really fix this.