Same problem for me. And I am afraid that if I begin the mission "The Hunt" it will make it so I can never complete "the scars we bear".

Read the Novels. Particularly TOR: Revan. 2 Sith purebloods are mentioned prominently in the book. One is a Sith force user, the other, had his station within the empire not as prestigious as it was, would have most likely have been a slave. He was a not force sensitive. A fact which caused the other sith much discomfort. So yes. It is entirely possible for Sith to be slaves. If they were weak enough...

Make sure all of your equipment is up to date. Mods should be at least lvl 16-20. Also helps to have kira updated too. any items that are not current level, purchase from the exchange. If nothing else, make sure your saber hilt/hilts are the best level you can get. I had just updated all of my equipment as a level 25 and the fight was trivial.

Unforseen Crisis? Am I missing something? Has some Bioware and/or EA employee somewhere said the sky is falling?