Blade Blast of Dagger Detonation not working with the Astral Projector

Hello. As the title says, this item/spell combination is not working; when I trigger this spell it triggers from my location instead of the enemy's. Even if Blade Blast is based on my melee weapon, it should still work, since it is both a spell and a nova. I've checked the wording on both and I don't see any reason for these items to not work together. I'm triggering it with Cobra Lash and Cast on Critical Strike. Is this a bug or am I missing something?

Another thing: the triggering seems to be kind of strange on Blade Blast. I have around 60% crit chance on my trigger attack yet Blade Blast only happens about 1 out of every 5 or 6 hits. I was using CoC with Shock Nova previously and it clearly triggered more often, as well as from the enemy's position. Just thought I should share as much info as possible about this issue. Thank you for your time.