Maybe it has to do with “Can no longer overwrite poison dot dmg with damage from toxic cloud more than once” from
This basically means poison clouds got nerfed, they cannot overwrite themselves over and over any more… which also means if you have an enemy which already is poisoned from toxic, toxic doesn’t spawn a cloud anymore (at least it seems like it from my experience).
Only if you have a monster which isn’t poisoned by toxic next to it, toxic will spawn a cloud (but the damage from that cloud will only be inflicted on the enemy once the old DoT is over).