When I select nightmare combat difficulty and set level scaling to "constant" (which is the default look the option menu have if you start a new game in Aesir difficulty) the enemies will NOT deal 200% more damage. Basically Aesir combat difficulty won't apply after you set level scaling to "constant" and you are left fighting in normal difficulty.
The story goes like this:
Recently I started a new fresh game in Aesir difficulty and realized the enemies were dealing almost no damage (easy or normal difficulty I'm assuming now). I went to check the option menu and saw the "combat difficulty" in "custom". I reselected the option to Aesir to see that level scaling changed to nightmare as well (enemies 60 levels above you). So I took that to "constant" again. Which I believe is the intended design of the game: Enemies will deal more damage, you will heal less and have less time to parry but they will be at your same level or the level stablished in that area. Resulting in deadly fast combat were you kill or be killed depending on player skill.
But that did not happened. Enemies were left doing no damage at all. Again, I believe the damage they would deal in easy or normal.
To "troubleshoot" this or prove my theory I settled the game in "Hard" (Berserkr) which by default has the level scaling set to "constant". And yes, now the enemies were dealing the claimed +60% damage of the difficulty description and scaled to my level (reasonable HP bars)
Drengr (very difficult) difficulty has the exact same problem as Aesir (both has to be selected with their respective Very hard or Nightmare level scaling, or they won't work).
If it helps: I know there has been a recent update adding the level scaling option in addition to these new difficulties. And my guess this is a new conflict after the last update. Because when I played the game last year in "Drengr" (Very hard, highest difficulty there was) the game worked flawlessly.
For me this is an obvious mistake that someone slipped during the recent update and left it like that.
I haven't make any pictures or videos because is easy enough to check in game for any developer (or anyone) and realize what I'm trying to describe. But I will if needed.
Thanks for the help.