There seems to be a bug regarding the Mannoroth and Varo’then fight. I can get to the fight, and even do the first kill (Varo’then) but once he drops his sword and Mannoroth starts his dialogue the NPCs and audio fade out, and I have to wait a few seconds for the instance to “reset” the fight. Once this happens, I can begin the encounter again, but only until that point, where it bugs out again. Ad infinitum, ad nauseum.
I’ve tried killing Varo’then as slowly as possible in case it’s a case of him dying too fast but at 120 and ilvl 399 he one-shots no matter what. The “reset” happens when I either click on the sword, or when Mannoroth is allowed to get a few lines into his speech after Varo’then dies. This probably isn’t a huge priority because it’s old content (which I totally get), but it would still be nice to be able to complete the instance for achivement/completion purposes.