I was more so referring to the player side of dealing with the effects, my experience when it comes to the enemies has been "welp guess we'll stand and wait for it to burn out... But that's been their response to grease as well.... Cleaver bastards.
That's interesting. In my playthrough it seems if they have difficult terrain but are not already standing in it they will avoid it.
However if they're already the effects they just run through it, taking additional damage, falling prone, and even dieing sometimes.
This is also why I suggested toning down the radius of the explosion and surface effects.