I’m pretty sure I remember bleed having different base values depending on weapon used previously. Though in this case I applied bleed using the heavy attack feat on the ogryn. The bash attack on the stubber counts as a heavy attack for this purpose, but is of course course a different weapon than the knife I also applied stacks with.
In both cases it only continues stacking to 30 damage, which seems abysmal, unless it scales higher as weapon rating starts increasing.