The normal layout screen uses Apple Maps. It saves the basemap data that you have viewed. Sometimes. It isn't really documented as to how long or how much is kept. So when you save a mission using Map Pilot Pro it will save the basemap data from another data source to use offline. You have to have at least the Base feature tier to do that otherwise you just have to use what Apple Maps gives you.
We can't have it save crazy high levels of detail for an arbitrarily large area. It adds up quickly.
Make sure you have the 3rd Party basemap selected. It looks like that is still the Apple Maps layers.