So by default, the Conduct Energy action from a Resonant weapon says it gives "1 additional damage per weapon damage die"
Conducting rune says "the weapon deals an additional 1d8 damage of the selected type instead of 1 additional damage per die; if the weapon already had the resonant weapon trait, it deals 1d8 damage plus 1 damage per die instead."
My question is, on a Conducting Rune weapon, does the 1d8 replace "1 damage per damage die", or does it replace "1" damage per damage die? i.e. does a Striking Conducting weapon deal 2d8 elemental damage?
Given that the language is "an additional 1d8 damage" instead of "1 additional damage per die" I'd say no, it doesn't scale.
It doesn't say it replaces the 1 with a 1d8, but specifically says it replaces the one per die.