I haven't looked at Explore in a while on my phone. It was prompting about its new features and warning I had to download offline maps again.
I deleted my prior offline maps and created an offline map area with a test area of trails and streets in California, selecting Topo and USGS layers. It showed downloading and as far as I can tell indicates that the map is now current and downloaded.
In "offline maps only" mode it doesn't show any text labels at any zoom level all the way to the most zoomed in for Topo layer. If I switch to USGS layer, it seems completely blank. As soon as I untoggle the "offline maps only" then it shows the USGS layer and labels appear on both layers.
Do others see the same behavior? It doesn't fill me with confidence to take this into the wilderness...
Version 4.15 (1602405)
Map Database Version --
Map Version 7.3.1
Edit: I decided to force stop and clear app cache. I also toggled the "auto download" on and off a bit. Now it seems to show some labels even in "offline maps only" view on my test map area, but the USGS quad layer still doesn't render. And the app info still shows that "--" for map database version.
