google-cloud-dotnet: Google Streaming Speech Recognition does not return responses

We followed example on official Google page for performing Streaming Speech recognition on an Audio stram.

There is a problem, that sometimes for sent audio chunks we dont get any kind ( of recognized) responses back. In next line of code NOTHING is returned back from Google.

Task printResponses = Task.Run(async () => ...

Is that expected scenario and what should we assume the problem was?

Regards