How to reproduce: Kill the bone totem in the mines in T1 of combat with one single attack.
Result: The quest doesn't trigger and your characters give no reaction to the destruction. Only the necromancers complain. The miners still do not talk, impossible to advance the main quest as you can't get through the big door.
Repeatable: I read of 2 other people who confirmed this (one here, one on Reddit). I have no savegame close enough to this point to try it again.
Comment: Not sure about what you exactly have to do, but it seems that killing the bone totem in one attack on turn 1 of the fight definitely triggers this bug. Maybe one of those conditions is optional.
I hope there will be a patch to fix this and maybe even fix it for those of us suffering from it. I had 10h of playing time (I thought there was maybe another component I would find later) since then and I don't really feel like playing all those parts with the same chars all over again.