#1 - May 16, 2016, 10:05 p.m.
In order to address issues with Dalaran NPCs suddenly disappearing, we've decided to disable the Underbelly subzone for the time being. Players with characters saved in that zone will be ported out upon initial login. We're currently investigating permanent solutions to dissapearing NPCs and should have the issue resolved in an upcoming patch.
Due to this change, Subtlety Rogue artifact acquisition questlines will be roadblocked for now. If you experience any other roadblocked questlines with this change, please let us know in your comments below.
Thanks for your patience everyone!