PoE1 Essence mobs not dropping essences when shattering them

Decided to boot up PoE1 again after not really playing PoE for a couple of months. Was running an ice shot deadeye in the campaign, and noticed more than a few times that essence mobs weren't dropping any essences at all (even with no filter on).

I put in a bug report in game, but figured I will put this here as well to see if anyone else is having this issue. Since I started in Necro Settlers, don't really have anything to my name yet in the league and those early essences would've been nice to have.