Commented Unassigned: can't pick files in offline mode [655]

This feels more like and Android OS configuration problem on my end, but I can't find anything here or on Google.

I'm using Keepass2Android Offline on Android 6.0. Whenever I choose "Open File..." -> "System File Picker" or ... -> "Get from third-party app" it just opens the Downloads app and never prompts me.

I've copied the database file over USB into my downloads folder, but the Downloads app doesn't recognize it. I've installed several different file managers including ASTRO and Amaze. I am never prompted for what app to use to satisfy the intent.
Comments: Well, I'm just an idiot. I was able to navigate around the Downloads app until I found my file browser, in which I could select my database.