title: Action doesn't handle one shot query
body: <p>I have an action that no longer works when issuing an utterance with "ask [invocation name] [utterance]"</p>
  
  <p>it just returns with a "The agent returned an empty TTS". </p>
  
  <p>However, if i set up nGrok, and try to debug it, the request never gets sent to nGrok and thus never hits my endpoint (backend code base).  </p>
  
  <p>Looking for next steps to debug this issue.</p>
  
  <p>Note, "Talk to [invocation name]" works perfectly fine.</p>
  
  <p>Also, if i use the "try it now" feature for utterance testing within dialogflow, with the same utterance, it triggers my endpoint.</p>
  
  <p>The intent that is to be triggered is set as "Implicit Invocation"</p>
  
  <p>While testing in the Simulator, Request tab is empty, Response is empty, Debug shows "the agent returned an empty TTS.", and Errors is empty as well.  StackDriver logs does not even show this request being made.</p>
  
  <p>While searching for other ideas, it appears this is possibly the <a href="https://stackoverflow.com/questions/59054593/the-agent-returned-an-empty-tts-when-action-is-not-opened-separately-to-asking">same issue</a></p>