Also when zoomed in all the way it did not show the minor roads. I just solved it by going to Settings » Data Cache » Check Now.
First I tried deleting the downloaded areas and zoomed in on Bandirma while online with WiFi, but it probably used the incomplete data cache. But it is still strange that it didn’t show all the information in the first place, since my last Data Cache update was showing august 5th, and I downloaded the maps on the 2nd of August. Or was this region recently updated in OSM?
I never used the update button before, because I had the ‘Automatic Updates’ set to Monthly. Now I have set it to Weekly.
It might be useful to have an update button in ‘My Destinations Details’, so when going to a certain region you can make sure these maps are updated, instead of downloading all your saved destination maps.