Fulmination from wrath sceptre doesnt trigger

i have tried just about anything but i cant get it to trigger with supports or without, with me appliying the shock or minions, with diffrent spells to rigger it aswell (lightning and phys spells)

It doesn't seem to trigger from most spells from what I tested as well.
I did manage to see it using a few spear attacks such as spear stab and Fangs of frost and even power siphon wand (that one is a spell, was a pain to test with the culling tho).
So either the gem description of "skill" is simply wrong and should be specified attack or the spell side is bugged.
Haven't tried with maces yet.

It looks like small arc, with some purple ray in it.
https://imgur.com/a/wgC6efg

Edit: I don't know if something happened since I tested, but it now seems to work?
I see the purple lightning with most of my spells "first hit".