Elemental damage with attacks works with grenade explosives?

Hi guys!
I have a question. I'm wondering about one thing, I recently replaced a crossbow that had physical damage "80-340" for same crossbow "80-340" but the second one has the addition "78% increased elemental damage with attacks" and in the skill window the damage hasn't changed, it's still the same. What does this value mean? is it a bug in the game that it doesn't show the increased damage or does it only scale after dealing damage/using a skill so that it's not visible in the skill window but it still works? Using explosive grenade skill on mercenary.

Thank you guys for ur answer and patient, have a nice day! :)

If you still have the same crossbow without that EDwA mod, you can test it yourself on any boss by checking the damage numbers on its lifebar. At least it would be reliable information.

There are other similar reports, but I can't say for sure whether it's just a tooltip display issue or an actual damage bug.