Jagoex at Warlock Therapy, it seems that the Warlocks' Seed of Corruption AE/DoT spell had been superbuffed to be: 2-3x, more powerful, instacast, require no mana and have a range of 60,000 yards. And if that wasn't enough, it could be cast even if the Warlock was dead. As you can imagine, hilarity ensued. As did a quick shutdown of the PTR Friday night.
When the PTRs came back up later in the evening, the spell was removed and all premade Warlocks had their talents and spell lists wiped. So not only do new Warlocks have to drop 350g to repopulate their empty spellbooks, they have to run all the quest lines to reacquire their pets. Needless to say, there aren't many premade Warlocks on the PTRs this week.
Still, it would have been fun to have seen the PvP matches before this mistake was caught.
EDIT: YouTube vid after the jump!