Marohi Erqi first+ strike heavy stun doesn't work on empowered bosses - bug or intent?

Hello, after launch of 0.3.1 I continued playing my Marohi Erqi build for bosses, however after using the Overseer Tablet in various map, the map bosses could not be heavy stunned with the first strike from this weapon. When retested on different map without using the Overseer tablet, suddenly this worked as intended.

This heavy stun feature had been problematic already before for some bosses (notably Zar Vali the Bone Titan and the Sun priest map boss).

I do not have Wind Dancer or Ice Armor? active, neither do I have any Thorns, therefore I always hit on full hp target with correct weapon. I have Dual Wiels, however even with that it has functioned properly before - now even with ME as a single melee weapon I cannot heavy stun empowered map bosses.

Can somebody tell me, whether this is intentional or a bug?

If intentional, please update the descriptions. Also nerfing ME (which nobody plays) is somewhat ridiculous compared to not nerfing Blood Mag
es or Deadeyes...

0.3.1 hotfix mentioned something about stun on bosses, however still doesnt work always.

it is rather inconsistent...some bosses (basic map bosses, or basic bosses with Overseer tablet or even some powerful bosses with overseer tablet) can be heavy stunned on the first try, while others cannot