meanbeard, AC1 Lead Designer and TD Designer, posted this bit of news on the Turbine Forums:
The Lugians are not giving level 126ers the appropriate XP reward because of a bug introduced during the final days of implementation. I would like to apologize to you for that bug.
I still want to give level 126ers the amount of XP you should have received for this quest. So, next month, take your Western Forge Essence to an Agent of the Arcanum. They will give you the appropriate XP reward. This reward will only be given once and will no longer be available once we publish the February event. If you have already given your Western Forge Essence to a Lugian, you will need to do finish this quest again. Of course, keep in mind that if you have already picked up a Western Forge Essence, you have to wait 30 days before you can pick up another one.
To be clear, the Agents will only reward XP for the Western Forge Essence, and they will only reward that XP to level 126ers.
