Mana for nothing (on Weapons)

I found out something funny while playing Marauder with Mace and an Infernal Blow + Elemental Blow Support Gem. I use infernal Blow with the right Mouse Button.

Now something (to me) quite unlogic is happening If I press Shift to make the Charakter stand still while hitting the right Mouse Button, (Infernal Blow) it costs Mana although I am hitting thin Air.

I think thst this should not happen, cause the Spell Cast by the Gem only should be Cast "On Hit" - that means if i actually hit a Monster or Chest - but not if I hit only thin Air.

The attack costs mana. The explosion is just an after effect of the attack.

ALL other skills be them attacks or spells (ex cleave, ground slam, burning arrow, split arrow) work the same way, with the exception of flicker strike if it's out of range.

Just because you miss doesn't mean you shouldn't have to pay any cost.

Thanks, thats what I was thinking already thats why I didnt write anything more about it. I compared other Skills and other Charcter Classes as well so i understand it now, if it´s the same fore all classes then thats alright with me.