Temple of Kopec - bug after boss

After beating the boss tried to talk to Alva but I moved off the platform, it moved up but my screen turned black.
Now my quest is at "Speak to Alva" but I can't talk to her.
After teleporting back to town and back in the platform is gone as well but Alva in town doesn't advance the quest either.

Bug Report ID: #431097993

Did you fix this? Happened to me also and im stuck there

Just died to a monster in the area before boss, after revival it got solved