title: The second follow up intent of my Dialogflow Agent can't catch the values of its parent parameters
body: <p>I'm building a chatbot which is abled to advice books. So, I need to ask gender, title and author. For that I made the intent "search-book" : </p>
  
  <p><a href="https://i.stack.imgur.com/hq80B.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hq80B.png" alt=""></a></p>
  
  <p>Then, I made a follow-up intent "Yes_Author":</p>
  
  <p><a href="https://i.stack.imgur.com/9Kj0H.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9Kj0H.png" alt=""></a></p>
  
  <p><a href="https://i.stack.imgur.com/sTiC5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sTiC5.png" alt=""></a></p>
  
  <p>And the last is the follow-up intent "Yes_Author_Yes_Title":</p>
  
  <p><a href="https://i.stack.imgur.com/UoFdG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UoFdG.png" alt=""></a></p>
  
  <p><a href="https://i.stack.imgur.com/2m7tI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2m7tI.png" alt=""></a></p>
  
  <p>When I try the conversation here are the responses : </p>
  
  <p><a href="https://i.stack.imgur.com/WKLRX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WKLRX.png" alt=""></a></p>
  
  <p><a href="https://i.stack.imgur.com/YJjkx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YJjkx.png" alt=""></a></p>
  
  <p><a href="https://i.stack.imgur.com/RIvRW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RIvRW.png" alt=""></a></p>
  
  <p>and the third call didn't take the Gender and the Author from previous intents. What is wrong ?</p>