My group encountered this issue yesterday with Black Talon. We went and did The False Emperor and went back and were able to zone in.

I've been comping some videos as our small group clears through: Check out what I've got so far, hope they help. http://www.youtube.com/user/zizzmasta

http://www.youtube.com/user/zizzmasta I've been making a few videos of the Hard Mode 4 man Flashpoints. Be nice to add to your collection. Hope they help.