Can't connect via bluetooth

I am running Sphinx on Debian Stretch. Kernel is 4.9.0-6-amd64. Sphinx starts up and it takes over the bluetooth interface but FreeFlight Mini does not find a drone. I have written an Android app to look at the bluetooth packets that are available when Sphinx is running but I don’t see any LE advertisements, which is what ARDiscovery is looking for (I found this looking at the source for ARDiscovery). I do see the device in my own app but no LE advertisement packets. I ran Sphinx with --log-level dbg and I see it finds the bluetooth interface and loads the bluetooth libraries. My bluetooth dongle is CSR8510 Venfor=0a12 ProdID=0001. I have used the Bluez btmgmt tool to turn on advertising just to test my Android app and it sees the advertisements, so it’s not that the dongle is not capable. Any ideas what could be happening?

I swtched my OS to Ubuntu 16.04 and it all works now so I guess Debian 9 is not compatible with Sphinx.