This part of the code from that thread will switch out of shift lock mode if it is currently active.
if MouseLockController:GetIsMouseLocked() then -- toggle shift lock off
MouseLockController:OnMouseLockToggled()
end
Setting BoundKeys.Value = "" prevents the hotkey from toggling it anymore. If you only disable the toggle key then it can be stuck if you disable it while it is active.
This broke it even more ;-; So the problem isn’t that the mouse is locked anymore, it’s more that the character is still spinning towards the mouse and the camera rotation is based off the characters humanoid root part.
I know I am very late, but a way you could go about it would be to change the camera subject to something other than the humanoid, and change it back to the humanoid.