Lionheart Season of Mastery Realm Temporarily Offline due to Transfer Exploit
Earlier today, on the Lionheart Season of Mastery Realm, players have noticed characters riding the Black Qiraji Battle Tank mount and wearing best in slot gear from PvP and Naxxramas.
It looks like the "exploit" to transfer a character from WoW Classic to WoW SoM was available for quite a while, which was enough time to make a huge impact in both the economy and PvP.