I completed the quest line to unlock Vale of Eternal Blossoms a few days ago.

Today, after finishing the last quest him in Krasarang, it gave me a breadcrumb quest "Temple of the White Tiger" to speak to Dezco at the temple. However he is not available (presumably he was in the phase before you have completed the challenges).

Suggested fix - this quest should not be offered to people who've already done the temple.