Breaking Progress Bug in Act 4

In the Quest "The Search" I killed the First Herald and died at the exact same time. The door to continue never opened, even after the instance reset, and the Boss Encounter is no longer available. I am left with the next step being to Confront Kanu and the First Herald and no way to get to them to do this. Complete stoppage of my progress. Please help. I opened a ticket and support told me to post here.