I reloaded. I reloaded to even being in Lower City before entering Wyrmrock Fortress. Every single time, killing the Banites on the first floor keeps me stuck in combat permanently, even after destroying the gadgets and traps. It's so annoying.
Look, you should make sure your turn-based combat queue is empty. This means you should destroy any flamethrower in the queue, as well as any grenade that is not blown up. Also, some nobles become hostile - they are not in the queue sometimes. Kill any of those that actually attack or use magic to make them friendly. When on the second floor (i.e. the floor with Gortesh hall), you SHOULD NOT be in combat.
I dropped combat from first floor by running to bridge and fleeing combat to camp. Came back. Lower floor non-combat. Upper floor not in combat, cutscene still does not trigger with me or Karlach. They just go into combat. I had to watch the damned cutscene on youtube, Act 3 has really put a damper on my game experience.
Not sure then

This place is obviously buggy, maybe you are too fast to reach Gortesh, idk...