Could be a bug, it really depends on what is intended.
But the Enemy Healing prevention relic perk canceling Blight’s effect seem to be against Siralim’s philosophy. I mean, the game seems to make the player feel powerful by building all these cool synergies yet equipping Dusk and Dawn at level (30-40+) cancels everything that is blight related.
Not sure if intended or not, but the whole game makes me feel like it isn’t. I’m guessing it really depends on how the blight is treated in the formula. Because do you still consider it “healing” if it ends up as damage? the relic seems to cancel the healing before it “becomes” damage.
Since this game is mostly on the enabling/OP-ing side rather than the limiting/nerfing one, it feels like Dusk and Dawn shouldn’t render Blight useless.