devtrackers.gg
By the way, I am not sure if this thread should be posted here.
It seems like Heartbreaker set give you one stack per bullet hit instead of one stack per shot (per "triggered pulled"). Therefore, we can almost immediately get all stacks by simply shooting few times with a high rpm shotgun.
This is causing people to face tank legendaries and melting everything becouse each shot will hit multiple bullets consequently giving you immediately huge armor bonus. I am pretty sure this is not intended not only becouse it is extremely broken but becouse the set is supposed to be used with lmg and assalt rifle (since it gives damage bonus to them). I have seen this issue in PC, but it is probably in console too.
If this interaction is intended this post can be deleted or ignored. If not, this should be fixed with high priority in my opnion, since a late fix would feel like a nerf to players and not a "fix" causing community issues.