Is Brink broken?

I use Overpower and Brink supports on my Leap Slam in order to prime mobs for stun with Boneshatter. The way this is supposed to work is that you jump on a pack with Leap Slam and prime them for stun, so they all display the white globes indicating stun prime. Then you follow up with Boneshatter and everything is obliterated.

The problem that Brink fixed is that the stun window is narrow. You have to get the mob to just below his stun threshold in order to prime him, but it you get to 100% of his stun bar, you instead do a heavy stun and he's no longer primed for Boneshatter. So Brink was added to fit this situation. What it does is limit your stun buildup so that it cannot hit 100%, thus preventing a Heavy stun, while doing enough to prime the mobs for stun, and follow up with boneshatter to execute them all.

But right now it doesn't appear to be working consistently. I Leap Slam on to a pack and sometimes kill a few of them, leaving others un-primed, and leaving me in the very precarious situation of being surrounded by angry enemies who are not stun primed and thus unaffected by Boneshatter.

Is this a known issue or am I misunderstanding some of the stun and Brink mechanics?

Thanks for any insights or suggestions.

What do you exactly not understand here ? Because from what I see, it work as attended. It's just that your leap slam either kill your target or do not inflict enough stun to bring them in the stun prime range.

Personally I use Rolling Slam and didn't see any problem with Brink so far.