Stun buildup issues

I have noticed some strange things with the amount of stun buildup that attacks do.

To test it I have use the same weapon, but using 2 "mace strike" by using weapon swap with 1 weapon.

https://imgur.com/a/3IaNA3n

From what I understand about stun buildup, the "mace strike II"(8k damage, 5500% stun buildup modifier) should do more total stun buildup amountthan the "mace strike I"((17k damage, 5000% stun buildup modifier)). (About the same stun buildup modifier, but way more damage).

But from what I experienced using the same boss and letting the stun buildup bar reset, the do both about the same stun buildup ("mace strike I" do a bit more) So it seems the stun buildup is unaffected by damage ? (removing damage support gem doesn't seems to affect the stun buildup, but the stun support do)

I also tested leapslam, it should do WAY more stun buildup (more base damage, 98% more stun buildup on the gem, consume armor break to get 500% more stun buildup, ...) but it also do about the same amount.

I tried with other weapons, and it seems to be linked with the damage of the weapon. So for the moment from what I can see, if you want to maximize stun buildup, you need:
- a strong weapon
- stun modifier
- no damage needed, in gems nor tree

Bosses seems to have a limit on how much stun build up get can get in a single hit.But it is not metioned anywhere in the game.I have the same issue like you, normal attacks dealing same stun as leap slam.

Yeah something like that could be a thing. But then the bug, is that there is not even one sentence about it in the stun tooltip.

Not having all exact stats is ok, but not knowing if "more stun buildup" really means "more stun buildup" is kinda frustrating when you try to make a build