Not sure if you are using a controller or mouse, but I experienced the same issue with my Logitech G502 mouse. It has a toggle mode for the scroll wheel and in the "free scroll" mode weapons would switch arbitrarily as the scroll would shift ever so slightly. Pressing down the mode toggle switch in front of the scroll wheel, i.e. using the other scroll mode fixed the issue for me.
English
-
I think you've nailed it. I use a Kensington Trackball. The ball has a capacitive scroll area on either side of the ball. I must be brushing that. It does change the weapons when I use it. Thanks.