Culling Threshold have the wrong calculation in party play

I've made a Witchhunter with 235% increased culling threshold which put the white monster's culling threshold at over 100% (instantly culled when damaged). This works perfectly in solo play but when a friend joined in this no longer works.

After testing, we noticed that by lightly damaging the monster down to roughly 80~90% hp, the culling mark appears again. We think that the culling threshold is currently being calculated based on the monster's based max life instead of their increased max life when in party play.

I've done further testing using a waystone with 49% more monster life and the 100% culling still works there perfectly so this should be isolated to the formula where monster life was scaled with party play (and not with any other monster life modifier).

I certainly hope that this is not intended.

Then the question is whether it is intended to work that way or not. Based on the wording on culling strike, the culling threshold is referring to the % of the monster life and not on the actual value (since increased monster life modifier did not affect the 100% culling threshold).

My guess here is still that the way they calculate the monster life increased for party play is using a different formula comparing to every other increased monster life modifier, and this is what causing the issue.