Copper citadel bug - Infinite Sandstorm

I was running the copper citadel map earlier today (Jan 16 when I originally sent an email and was redirected here this morning) on my storm weaver character. When I got to the boss arena the NPC Asala did not follow me into the arena.
I have experienced this bug before in the campaign, however I didn't report it as it only happened once and it was inconsequential. I didn't lose exp because it was low level obviously and there was no Keystone at stake in that attempt, but I digress.
I lost a run that I was almost certain to win. I quickly got the boss to just over half of his hp bar prompting him to use his sandstorm attack that Asala would normally protect me from. When I realised, I was going to die I quickly exited to character select hoping that when I returned Asala would be ready to join me in the fight the second time around. She was not. Not only did she not help me, the boss was now eternally stuck in the sandstorm animation spawning in a never ending horde of mobs moving around and attacking whilst still glitched into his sandstorm animation.

I tried a number of things including recruiting a good Samaritan from global chat to burst him down to the point where he cuts the caravan in half to start the second sequence of the fight, but they were quickly melted before they could loose more than 2 arrows on him. At one point before I entered the arena, the sandstorm actually started to hurt my character while I was standing outside of the arena by the bugged Asala NPC.

I'm not happy. I feel cheated. I spent hours searching for that citadel and now I have less than nothing to show for it. -10% exp at level 92 is around 3-5 maps which is at least 40 minutes down the toilet, not to mention the time I spent searching for the citadel (this was before the patch that revealed them through the fog) and the value of the keystones I lost in addition to any potential drops from the boss himself.

I have attached a video link of the last 2 minutes I spent outside the arena before going to face my inevitable doom so you can see exactly what was happening for yourself.

https://youtu.be/ShktnLMsTgk