Kaivax has posted on the official WoW Classic forums that they have rolled out a bugfix that corrects the exploit that allowed instance encounters to be completed repeatedly.
We’ve recently become aware of a bug that could be exploited to allow instanced encounters to be completed repeatedly. We have developed a fix for the issue, and we are in the process of deploying it worldwide.
Realm restarts are scheduled for 3:00 a.m. PDT (6:00 a.m. EDT) in order to apply this fix.
As soon as possible, we will identify those who knowingly abused this bug in exploitative manner. We will then take appropriate punitive measures.
As a reminder, Blizzard’s End User License Agreement defines cheats as “methods not expressly authorized by Blizzard, influencing and/or facilitating the gameplay, including exploits of any in-game bugs, and thereby granting you and/or any other user an advantage over other players not using such methods.”
As always, thank you for your feedback on this matter.