Eternal Nature passive wording was changed from “Companion Spell Damage” to “Minion Spell Damage” this patch, but testing on both totems and spell casting vines I see that it is not giving minions flat spell damage.
I don’t know if this was a typo on the updated passive tree and it should still say “Companion Spell Damage” or if this is a bug and it should be applying the spell damage to minions, but isn’t.