Slight controller analog stick inputs cause glitchy walk/run state with keyboard input
If the left stick on a controller is tilted slightly, but not enough to cause motion, then "walking (with WASD) in a straight line" and "walking (with WASD) while turning (with the mouse)" disagree about whether the player is trying to walk or run.
Example at beginning and end. Middle section is showing how it doesn't happen with "autowalk", only WASD input.