I believe there may be a missing spawn location for the abberation bounties of the Society.
Every so often, a bounty is reported for a creature in the "Lowerdark". There are several locations I know of that qualify as "Lowerdark" in which I will typically find them. However, every so often, one of these Lowerdark bounties is offered that simply cannot be found out there, anywhere. I've spent literally hours searching, without success. I've even returned to check on the state of the bounty, to discover that it of course has not been turned in by anyone.
PM me in IRC if you want to confirm the locations of the spawnpoints that I know of, and compare them to those of the bounty system.
IRC - Magister
I thought some of the bounties could spawn in quest areas, or I could be mistaken and they are just abberation heroes and drop the bounty heart regardless.
Actually, what I've found usually is the case is if you can't find it, a wildling PC found it before you and kept the heart.
More likely what Pigadig says, yes.
I collected several 'Aberrant Heart' objects from herospawns during quest, for what it's worth.
I know druid PCs and other non-Sanctuary characters do often get these before Society members, and the hearts are kept as trophies. Nothing else for non-Sanctuary PCs to do with them.