Rogue quest issue (level20)

[sorshha]

Quest-The Shattered Salute
NPC-Shenthul
Character Name- Until

Cannot complete this quest. I accept it and /salute him.
He says well done and I cannot click "complete quest".
It is highlighted as if it has been complete, but clicking it does nothing.
Eventually it turns into a failed quest.
This has been for a few levels now.
I have dropped it and reattempted it multiple times now.
This is kind of an important quest line.

[Humility]

Bump. I'm experiencing the same problem. Please fix Do something. Anything.