Noticed thanks to some Accursed Experiments nodes that either have permanent bleeds, permanent heavy bleed or timeless heavy bleed.
If Blood Drive is inflicted with a heavy bleed or a permanent heavy bleed before getting any stacks of bleed, she will still attempt to remove all of them but only get one enrage. If she is inflicted with stacks of permanent bleed before getting any stacks of bleed, she will get enrages equal to the amount of permanent bleed but not of regular bleed.
Basically, Blood Drive tries to remove all of her bleed related debuffs, but only gets enrages for whichever one was applied first.
If Blood Drive is inflicted with a heavy bleed or a permanent heavy bleed before getting any stacks of bleed, she will still attempt to remove all of them but only get one enrage. If she is inflicted with stacks of permanent bleed before getting any stacks of bleed, she will get enrages equal to the amount of permanent bleed but not of regular bleed.
Basically, Blood Drive tries to remove all of her bleed related debuffs, but only gets enrages for whichever one was applied first.