Pressing RMB + LMB cause weird glitch when Playing Games.

[D0R1T0S_]

(sorry for my bad English)
When i press RMB LMB together, than suddenly aim moves to bottom right of the screen instantly.
This glitch is making me crazy. please help!

 

[JTMC68]

Can you add a little information?

What games does this affect, do you play in fullscreen/borderless/windowed/???, does it happen with a different mouse as well?