I have scoured the internet high and low for some answers about what Damage Reduction actually does against Combusting Wounds. I'm pretty sure that normally for other DoT effects, Damage over time just subtracts DR from the total and just retains the ratio somehow. ie:
10 damage over 20 seconds, DR is 8, so 2 damage over 4 seconds since the effect is .5 damage per second. It wouldn't be 2 damage over 20 seconds.
Although I just tested Necrotic Lance and base damage for Aloth should be 17.7/6.5 seconds (2.7 dmg/sec) and it was reduced to 10.8 dmg/3.3 seconds (3.27 dmg /sec). so, idk.... it's close to being the same ratio?
Not sure how it works with Combusting Wounds though, it might very well be useless if the enemy has a DR of 5 and above.
These are the possibilities I can think of:
1) It could be adding damage to a total/pool to occur over the remainder of the effect, so DR would soak the first x amount of damage and the rest would get through.
2) 5 burn damage is simply stacked on top of whatever is hitting the enemy i.e. [(21 pierce dmg + 5 burn dmg) - 11 DR] = 16 total dmg
3) 5 burn dmg is just applied on it's own when the enemy is hit which would make it useless against an enemy with a DR of 5 or above.
I've spent so much time figuring out how nearly most other parts of the game work but this.... this just eludes me 8/. Especially considering that the side panel just says the effect is active, but there are no ticks for damage being dealt or anything. Otherwise really enjoying hard difficulty on my first playthrough!
Help me Obsidian community, you're my only hope.