1) it's not a still and the subject moved.
2) hasty making technique -- this stuff can be painstaking.
The feather value does not change or offset the mask path. It looks like the path is not accurately drawn. You have applied the liquify filter and there are keyframes so I'm assuming you are distorting the layer. Turn off liquify and you'll probably see the mask snap back into the right position.
What you have here is a rendering order problem. Masks are rendered first, then effects, then transformations. The layer is distorted after the mask is applied so this has moved the face and not the mask. If you really need the mask to stick right to the face then carefully roto the face (rotobrush should work very well on this layer, then pre-compose and apply Liquify.
While the screenshot helps diagnose the problem I have no idea what you are trying to do or why you have applied the mask. Knowing that may give us some other ideas.