+1 for /console rawMouseEnable 0 fixing the camera moving around on its own, but not the mouse randomly moving back to the middle of the screen.
Related: Alt-tabbing in Fullscreen Windowed Mode on Win10 isn’t always allowing my mouse to go back to WoW. If I alt-tab to Firefox and try to move the mouse back into WoW, the mouse cursor can’t leave the Firefox window–the mouse “flicks” back into the Win10 window over and over again until after like the 5th try, the mouse is back in WoW. I’ve replicated it with Windows Explorer to exclude it being a Firefox issue, but I can’t trigger the bug itself.