Re: Skype for business is pretty sad
2-3. It's not a Bluetooth problem because it also happens with me with a Logitech headset and their USB dongle.
Seems if the connection to the headset cuts out and returns for whatever reason, Lync doesn't realise that it's come back and just carries on piping silence to the call.
As for network configuration, no other IM/voice call/video call seems as flaky as Lync. You are forced to make sure layers 3-4 are set up just right for it because layers 5-7 can't cope gracefully with errors.