The plugin offers a preview option that updates the layer or point's position so the user can see the result.
Sadly each time an object moves on screen Sketch registers it in its undo stack.
If the user moves an object for (0, 0) to (100, 100) using the plugin it's normal that it can be undone.
Now if the user tried (50, 50) then (75, 75) to finally set it to (100, 100) the first undo will place the object to (75, 75), the second (50, 50) and finally (0, 0). If the user cancels the move then the undo stack will be (0, 0) -> (100, 100) -> (75, 75) -> (50, 50) -> (0, 0).
Now if I'm able to disable the undo manager every user's action won't get recorded and thus allowing a clean undo stack in the event of a cancelation or a unique undo entry in the event of a validation.
So we can say that I just want the user to be able to undo what intended to do in the first place.