On death explosion preventing Nameless Seer from spawning?

Hey, I have ran a lot of maps this league and got like 5 nameless seers while completing the atlas.

After that I've acquired 100% on death explosion chance (haemophilia) and I've farmed almost 500 maps, fully clearing without having a single nameless seer spawning.

I'm pretty sure something is preventing him from spawning, since as far as I understand certain packs on death cause him to spawn, and on death explosion might be messing with it.