Volume unknown immediately after reconnect

Log contains the Bmap error response:
```
2020-06-26 19:33:04,891 BoseThread DEBUG 4C:87:5D:53:F2:CF <-- Packet(function_block=<FunctionBlock.AUDIO_MANAGEMENT: 5>, function=<AudioManagementFunction.VOLUME: 5>, operator=<Operator.ERROR: 4>, device_id=0, port=0, payload=b'\x07')
```