(Classic) bluetooth service scan sometimes hangs indefinitely on Android

Starting a QBluetoothServiceDiscoveryAgent(FullDiscovery) sometimes hangs forever.

Detailed analysis is still pending but at this point I venture a guess of what is happening:
First everything goes as usual:

• First the device discovery is done
• Then the service discovery kicks in
• All devices are discovered for their services

However, if the device for whatever reason fails discover any services on any of the devices *), the internal "sdpCache" will not get any entries. Then, on the last device's service discovery, the code calls (via timer) this function:

https://code.qt.io/cgit/qt/qtconnectivity.git/tree/src/bluetooth/qbluetoothservicediscoveryagent_android.cpp#n425

But since the sdpCache is empty, the function immediately returns and the discovery won't get finished. I guess the sdpCache.isEmpty() is interpreted as "service scan has been stopped already", but in this corner-case it doesn't hold true.

*) A way to reproduce is to unpair first all devices that are in vicinity (and possibly also clear device's bluetooth caches)