There seems to be a weird interaction that may not be working as intended when using a boosted drain life from inevitable demise after casting soulrot. If any mob that is being drained during the boosted drainlife dies the bonus damage is lost on all targets being drained.
It does not matter if it is the main target that you drained that dies or one of the extras that is being drained due to soulrot.
This is awkward because if soulrot hits a low hp target and you begin a big drain life it will be wasted if the add dies in the first couple of ticks of damage.