Your force stop key (Shift key) is not working properly. If you press it before you move/attack then, yes, it works. But if you press the key after you’ve already started moving/attacking it doesn’t.
This is the only ARPG I have played (and I’ve played them since Diablo 1) that doesn’t do this properly.
If I press shift, the character should never move no matter what.
Additionally, it doesn’t seem like this key is available in key bindings either.