A recent thread on the World of Warcraft forums points to an issue with characters mysteriously deleveling, or in some cases, missing entirely on Khadgar, Customer support says they have been made aware of the issue and they are looking into it.
The issue began on September 22nd and has yet to be resolved. As of the 24th, customer service states the work is ongoing, but a number of characters have been restored to their previous levels. It has been indicated that they consider this a “high priority” as indicated on an update yesterday:
“As many are aware, this has been a very high priority for us since it started.
We’ve reached a point where we fully understand the issue and we will continue working to resolve it. Players who have missing characters or de-leveled characters should start to see what they expect returning this evening.”
With World of Warcraft: Shadowlands just around the corner, and some recent "realm connections" that Blizzard has implemented, this issue may have come at a most inopportune time. While we hope for a speedy recovery for those affected, we will continue to update everyone with more information on this problem as it becomes available.