Regarding nemesis revive ability!

So regarding the ability that nemesis revive after short period which seems to be within 1 turn every time. This poses a problem with sigils of +hp%.
I had a +230% hp Sigil and each creature was 150k+ hp. I beat them all over several times but it was impossible to kill them all in 1 turn.

Would it make more sense that each time they are killed they take longer to revive rather than 1 turn every time? I love +hp sigils because my team does colossal damage in 1 round but that was serious dps to actually beat that. Would like to see this nemesis rebalanced a bit so more a creature is killed it takes longer before it can respawn.