Arsonist Command skills drain your mana even if they don't go off

Doesn't consume cooldown, just lets me drain my own mana for no reason. Doesn't seem intended.

I'm using Skeletal Arsonist: Explosive Demise. Keep running out of mana from pressing the non-feedback button in vain.

(because the targeting is kinda terrible too, but that's harder to fix; I think it depends on the enemy I'm mouseovering and the distance to my minion)