Files downloaded from Dropbox with umlauts are never displayed in the media library

When using the latest public version of VLC-iOS (3.1.9), downloads from Dropbox with umlauts in the file name appear to work correctly (the progress bar comes up, etc.). However, after download concluded, they never appear in the media library.

This appears to be a regression from previous releases.

I tried to reproduce the problem with the master branch, but failed as Dropbox logins don't seem to work with the public beta of the app.