Known issue: CMB can't currently handle the 7.2 empowered traits. It will try to empower items that are at their maximum power if you didn't unlock the additional traits, which results in the "your weapon is at its maximum power" error. Also it will try to use items that were gathered before you empowered your artifact which results in the "your weapon is too powerful" error. I'm looking into this. Thanks Blizzard for this "don't stockpile AP items" blocker. $(%&ยง)/()!
Look a couple of posts back. I've attached the most recent version there until Jimmy gets back and makes it official.
AP got simplified a lot with 7.3, so the next update will remove all the compendium and tome related special code and the empowerd traits will no longer be an issue.
