Getting annoying with skill placement

So I am going through my uptenth leveling of a new character. I have noticed a rather annoying problem that happens evertime i go into a loading screen or die. That problem is that the spell I use from my staff seems to replace itself on one of my mouse buttons instead of staying on the q button in which i have assigned it. I did not have the problem when I was using a magic/rare staff but when using Dusk Vigil it occurs ever freaking time and it frustrating and annoying. Is there a way to stop this or no? or is it a bug?