Elemental Damage bug? - Conversion or Added

Hi,
it seems that the elemental damage infusion is lowering the overall damage output.
After infusing the weapon it hits way less. Is the elemental infusion not added? That would mean, that the physical damage from the weapon doesnt add to the ele damage and is only a “conversion”.

with this setup there is sadly no reason to put a ele gem in your only weapon slot.

it would be really nice if somebody from the team could clear this up. There are a few reports on reddit too. i am hesitating right now to use a gem if this bricks my main weapon.

Thank you!