"You do not have the quest state" bug - lost character to it :(

So I just got a HC character to act 2, and while I'm clearing the map for leveling pre-Rathbreaker and tried to fight it while I thought I could - mid-fight, I try to "back to checkpoint" realizing I'm too weak, and instead of it working like normal, I get a chat message along the lines of "You do not have the required quest state".

GregoryHC did not make it out alive...