Horrific vision as caster

[Stormgnoef]

Having no problem at all, did you upgrade your visions skill tree?

Also this. 15 % dmg reduction and increase helps a lot and its fairly easy to get

[huth]

What I did was CC one guard and burst the other one, its too damn hard to try to do them both at the same time as a caster. That fire affix is a bitch, indeed. What I did most of the time was just spam sunfire / moonfire (with azerite to hit additional target) and just run around.

The trait only triggers when you move. Stand still and it doesn't do anything. I also had absolutely no problems with the guards as a lesser geared moonkin. It's also not fully random, you can see flames around you when it is active and it will always move you in the direction you're traveling. If there's a pack in front of you and you don't want to pull them, don't move in their direction.

Then on my second run half the first district decided to gang up on me all at once for no apparent reason...

But you get 31250 CV + 1 Vessel just from quests after the daily buff, so messing one up isn't quite as bad.