That is odd, every other time I see reported it’s a gamepad causing the problem… hmmm
Is it rotating constantly in one direction only or does it rotate following the mouse position? If it follows the mouse, check your left and right Alt key to make sure it isn’t stuck. Also check your Arrow keys & W A S D keys. If you use a program like AutoHotKey, disable it as well to see if that helps.
If that doesn’t help could you describe it a little bit more, such as is it rotating around a point in the world, or is the world camera just moving to the right/left? Is it constant? Which version are you using?
Thanks! 