Fixed as of yesterday's maintenance. (Oct 21)

They fixed it on the US realm as well as the EU realms, as it worked fine for me. I know there was some question as to when they were going to implement the fix they found on the EU servers in the US servers, but I guess they just used the same solution. After the patch I was only able to grant 4 levels (level 59lock granting to my brother's account) and yesterday I was able to grant the rest of the levels and jumped his shammy from level 40 to 58.

EDIT: whoops, didn't see the second page of posts confirming the fix, my bad :P