Meters already have a fix for Soul Capacitor, so, maybe is another issue.
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This method is a fun way to know about the leeches, but, unfortunately not fully accurate.
The reason 1 is we don't know how much leech % the player has on its gear.
Reason 2 is about overhealing, we don't know which trinket healed, which overhealed or if the player's gear leech healed and leech from the trinkets overhealed, the only workaround is dividing the 'done' amount.
Details! has the tech to know how much leech the player has on gear, but still, have the overheal issue.
It's a pointless discussion, you give leech to someone else, and he heals from that buff. And since this heal come from outside of you globals it would incorrectly infiltrate healing meters if someone has the trinket.
Countig this towards the trinket owner is like couning damage done for a warrior who gives battle shout, or a shaman who uses bloodlust and so on.
At least this is my opinion.
Also i found this lolbug that, leech can heal you even if you are a ghost, and you still have dots up on something near you. Which is pretty funny actually.