Here is the thing. Actually, this is related to my other post before.
I have to shift node by an offset in order to paste the objects in the clipboard to another layer at my lastInput position.
Accordingly, I need to update links position as well which I believe should be calculated automatically via new position of linked node. So I have to call invalidateRoute to force it happen. Otherwise, like what I mentioned, I have to drag the node a little bit after paste in order to trigger that function happen and update my link.
-Chuan