Tempering The Blade (Horde)

This quest is part of the quest chain.

Objectives
Myralion Sunblaze at Quel'Delar's Rest wants you to temper the Reforged Quel'Delar in the Crucible of Souls.
 * Tempered Quel'Delar

Description
At last, the pieces of Quel'Delar are rejoined and the blade is whole, but it cannot see battle until you have tempered it. That jagged saronite edge is brittle and will shatter the moment it strikes anything.

Deep in Icecrown Citadel's Forge of Souls is a place where the blade can safely be tempered. Take Quel'Delar with you to the abode of the Overseer of Souls and look for the crucible. Plunge the blade into the crucible to temper it and bring it back to me.

Rewards
You will receive:

Progress
Until the sword is tempered, it will be useless.

Completion
Tempering the sword should've restored the blade. Why hasn't it worked?