Sometimes SDK returns wrong SpokesResponseDeviceInfo object

I have observed this situation several times: I have active connected Plantronics headset (in my case it's savi w720) and when I leave my pc in idle state for some period of time,  I receive unpredicted response from SpokesResponseDeviceInfo response object with an error and description - 'There are no supported devices'.  I have not found any other way to fix this other than to manually 'restart' dock station by power off and then power on it back. Any ideas why it can happens? Thanks.