This one is a bit odd. While crouch walking forward or backward, my right (d) key is unresponsive. Also, if I hold crouch, forward (w), left (a) and right(d) and let go of left (a), I continue to go left as long as my right key is pressed. If I use the arrow keys instead of ‘w’, ‘s’, ‘a’, ‘d’, everything works fine. This seems to only be a problem with the ‘d’ key as I changed my controls to ‘e’, ‘d’, ‘s’, ‘f’, and the ‘d’ was still bugged.
Maybe this is just me and my keyboard, so if anyone else is getting this same problem, let me know.
EDIT: Mustang was correct, its my keyboard ghosting.