Soul Tether, Chaos Inoculation, and Mystic Harvest

Using Soul Tether with "Excess life recovery from leech is applied to Energy Shield" mod intact after cultivation, whilst playing as Amazon with Chaos Inoculation, Mystic Harvest, almost all damage being elemental, and with the only source of life leech being on gloves results in no energy shield recovery.
My max health is obviously always at 1 therefore all life leech should by default be excess life leech.
"Energy shield recovery from leech" does briefly appear on the character sheet right after a hit, but no recovery is applied.
Having Fast Metabolism notable allocated does fix this issue however, and from what I read on the forums Leech III support gem does so as well.

I shouldn't have to use up an anointment slot, path 20+ passive points off course, use a Megalomaniac jewel, or dedicate a support gem slot in every single damaging skill I'm using just for this interaction to work properly.