Unable to move Mapster, but I'm certain that previous versions allowed you to relocate where on your screen you wanted the map to sit.

You can move the map by grabbing it by any of its "frame" (click and hold, drag around), basically anywhere there is no actual map or any other button.

@Desdemonique had the same issue, mine is because ELVUI did some cosmetic thing on top of the map frame. Disable the zoom options in elvui fixed it