Wasn't sure where to post this but I wanted to know of other people had this problem, I found since the last patch that there has been an issue with the Peacekeeper bleed effect.
This may apply to other heroes too but so far I have only experienced it with the Warden. After a guardbreak - triple stab, the bleed stacks up and an amount of the healthbar turns red, then after 1 tick of bleed damage the bleed is cleansed and no longer deals any damage.
This also happens with the Nobushi bleed effect from her retreat and the Peacekeeper dodge heavy, would be really useful if this got fixed, a character who relys quite a lot on bleeds not having them work is kinda making her really weak to play, as I mentioned above so far I have only expierenced this on the Warden, but a friend tells me he has had it with other heroes too.