Implacable - Damage dealt to Saltpyre is reduced by 20%. A further 20% of incoming damage is dealt to Saltzpyre over 3 seconds. Saltzpyre cannot be killed by damage dealt by Implacable.
Barkskin - Taking damage reduces the damage you take from subsequent sources by 40% for 2 seconds. This effect can only trigger every 2 seconds.
I went on the modded realm to test (legend difficulty). I spawned one Chaos Warrior, and had him do the walking overhead attack. This attack has always done 100 damage on Legend. It initially did 60 damage, with another 20 after the fact, as Implacable describes.
I went back in with Barkskin, and performed the same exact test. Same damage. 60 initial, 20 after the fact over a period of 3 seconds.
66% (2 of the 3 seconds) of the 20 damage should have been mitigated by 40% through Barkskin
20 x 66% = 13.2
20 - 13.2 = 6.8
13.2 x 40% = 5.28
6.8 (usual damage tick) + 5.28 (2 barkskin damage ticks) = 12.08
Each second of Implacable deals 6.8 damage under normal circumstances. (it’s actually 6.666667 but I don’t need to be that precise to make my point…just think, slightly less than 7 damage).
Rounding to whole numbers, I should have taken 60 impact damage, then bled for 12 damage. With Barkskin I should have taken a total of 72 damage, not 80.
When it doesn’t work with the one passive in the game it would synergize perfectly with…this has got to be a bug. If not, it needs to be better articulated within the game.