"Intel Device Validation for UPnP Technologies" tool gives NOTIFY errors - how to fix it?

I'm implementing a UPNP device and testing it with Intel Device Validation for UPnP technologies tool.

I noticed that the tool failed a few tests, and one of them is "Discovery/Notification Test Suite - Notifications" and it gives the following error messages:

NOTIFY <<upnp:rootdevice>> MISSING/LATE
NOTIFY <<urn:schemas-upnp-org:device:MediaRenderer:1>> MISSING/LATE
NOTIFY <<uuid:b9c29db6-6b02-4e4d-8bef-192f2ab8ce0b>> MISSING/LATE
NOTIFY <<urn:schemas-upnp-org:service:AVTransport:1>> MISSING/LATE
NOTIFY <<urn:schemas-upnp-org:service:ConnectionManager:1>> MISSING/LATE
NOTIFY <<urn:schemas-upnp-org:service:RenderingControl:1>> MISSING/LATE

Then out of curiosity I ran the same test on Intel's own MediaRenderer demo application and also on SONOS PLAY1, and both gave the same errors. Despite the errors, my SONOS PLAY1 works just fine.

What does this test actually mean and what should I fix in my UPNP implementation (I'm using Gupnp) to pass these tests?