I have noticed that areas that I have driven and had access to edit, have now become un-editable as if I had never driven there. Can anyone explain this?
Your editable area will “expire” approximately 90 days after it has been gained. So if you drove in this area last May and have not yet driven there again since, you will have lost the area.
The only way to retain the area is to become an area manager for that area - but even then if you have not edited in that area after 90 days, it may be deleted.