Hex Bloom + Decaying Hex

When an enemy that was cursed dies, Hex Bloom spreads hexes, but Decaying Hex does not affect spread curses. Only on first cursed enemies It's a bug?

Hex Bloom + Impending Doom, Hex Bloom + Heightened Curse working fine (spreads upgraded curses whith this support stone)

And, yes, i'm used it like a curse, not aura with Blasphemy.