I have been able to replicate the issue. It seems to happen when you try to edit a label that is the child of a landmass you just pasted. It doesn't happen when putting a new label on the pasted landmass or if the copy/pasted label is a child of the canvas.
Thanks for letting us know! We'll have this fixed for the next version.
-Katie
Afterimages that will not go away
Moderator: Kyete