Imported maps created in project folders not retaining there information after closing Unity

Map Magic version 2.1.11

To recreate the problem make an import map asset using a texture file. Use it in a map graph, works fine. Quit unity, then log back in and the graph map will fail to update. If you check the imported map, the information about the texture file which was used to create it is no longer there. Am I missing some step? Do I need to bundle it in an asset bundle or something?