DLNA/Upnp regression: empty folders

Regression since 3.5: reinstalling 3.4.4/3.4.3 nightlies do not exhibit the issue. Tested on an ADSL TV box (Bouygues), a Samsung Tablet and a phone.

DLNA server is serviio.

1. Access the Serviio server
2. Enter a folder
3. This folder will be most often empty, sometimes will just list subfolders and very infrequently, show the expected content.