Currently, the VelocityX and VelocityZ parameters available to animations do not perfectly reflect your actual movement.

If you are running forward and let go of the joystick, you will notice that you come to a complete stop before the velocity parameters actually reach 0. This can be observed in the debug menu.

To provide context: I found that by disabling the "Force Locomotion animations for 6 point tracking" option, and manually implementing a "Moving" state in the locomotion animation layer, I could make a toggle in the expressions menu for whether or not I want the walking animation to play when I am moving.

Unfortunately, because of the aforementioned inaccuracy of the velocity parameters, there is a noticeable delay between stopping movement and the state transition that will cause tracking to be reenabled for the legs and hips.

Edit: Alternatively, to avoid compatibility issues it might be better to add new "raw" velocity parameters that are not smoothed like the existing ones are.