Sometimes, when im using a spell thats on say 4 or 3, it will instead cast the spell my mouse is hovered over on the Y axis of the screen. For example, im using 4, but my mouse is held down near my character very far up over skill #7, and for some reason sometimes, will cause me to CAST skill #7.
i'm just using skill #7 as an example because it varies between 789 because that's where my mouse usually rests. Please be assured i am not using any other keybinds to activate 7 nor am i clicking it.