Double Skill attack bug

So I was playing with my marauder using ground slam (I think that is the name), and suddenly I saw that he sent 2 ground slams, with no cooldown. I tried to reproduce it and I got that when we use right click (idk if it works with other hotkeys, I'll try later and post) to send skill, and immediately press shift, we release 2 skills intead of one, though MP consumption remains, this can be used to exploit the game. I read the known issues and didn't find anything like that. So I'm sorry for my bad english, and no images/video now, cause i'm hurry to go to my job, after I come back I will get a video showing this bug!

Steps to reproduce:

-bind ground slam to mouse right click
-right click somewhere
-immediately after you right click the mouse, press shift

So it releases two skills instead of one.