I'm experiencing this DirectX issue all the time. Usually happens in dungeons, however, its just happened then while stood in New Gridania while waiting for the levelling roulette.

Most of the times I am finding this happening (while playing WHM) during casts of Holy or Assize.

!! MINOR SPOILERS BELOW !!

Happens regularly on the boss in first dungeon of Endwalker where your hitting that certain shaped object on the raised platform. The explosion at the end of that phase causes the crash.

Second dungeon of Endwalker, second boss, just after the fight starts and the first large aoe lands. Not sure if its the boss mechanic or the Assize that I cast but it crashes every time at this point.

Literally, just crashed me out now at the last boss of Haukke Manor while we were all stood at the door waiting for one of the other group members to catch up. Playing Red Mage.

Edit for system spec

Windows 10
i7-8700k
1080ti
32GB
Running off SSD