I go into “Advanced” under Keyboard Settings, uncheck “Fast Weapon Switch”, click “Apply” or “Okay”, and then once I view the “Advanced” menu again, the box is some how re-checked. If I leave the advanced menu and then re-open it without clicking “Okay” or “Apply”, it remains unchecked.
This wouldn’t be something I’d worry about if the weapon-selection graphic showed up on fast switching like it used to, but it does not.
EDIT: Forgot to mention, I’m on the Public Beta build.