Right Stick turns but also switches weapons, please help

I have the same problem as this user here on Steam.

SEATED + TURNING = WEAPON SWITCH wtf?

Just quoting this to show this is not a single instance.
Now as the topic says the right thumb stick which is supposed to be for turning
also switches weapons when turning without the B button (weapon radial) is being
pressed. This looks like something is wrong in the ini files. Can you please fix this or at
least let us know what needs to be rewritten in the inis. Thanks a lot. Game is unplayable imo with this bug.