Plutonium

In the Zombies mode of the game, I'm experiencing an issue involving player movement being slow when aiming down sights, walking backwards, and after knifing a zombie. It isn't an issue involving the timescale, but rather that the game acts as if I'm using a controller and I'm moving my left stick only slightly instead of fully (my gamepad settings are disabled and I am playing on a keyboard and mouse). This issue has been persistent since I've first attempted playing Zombies mode. The only maps I've tested that has this issue right now are Green Run Town and Nuketown in Solo mode. I've tried looking online for solutions to this, but they only assist with jerky mouse movement issues, which I am not having and have not been having. Any help with fixing this would be greatly appreciated!