I found this out the hardway. Normally I run with Verbum desktop, and a see-if-they-fixed-it Logos Mobile app. This time I decided to use the Verbum Mobile app.
But deleting the Verbum Mobile app gets mixed up on macOS, with Verbum the desktop app. Bad news.
Now, did it delete the actual resources, or the library data? I'm guessing the library data, judging from the pattern of slow failure.
That was after another bug this morning. If you open a resource while logged in (and the resource is not downloaded), and then later re-start the app offline, it doesn't know what to do (generic file unfound) and that's that. Ergo needing to delete the app (though probably I could have re-started online, but I'm not using the mobiles anyway).