Yes/No intents do not seem to go through the NLU threshold, while the chatbot is trained on stories in which yes/no intents occur. What could have led to this low estimated NLU threshold for Yes/No intents and how are we able to account for this issue?
The following story illustrates the problem 
“Hi”
“Hallo”
“I would like to get a ESTA for travelling abroad”
“Great! Do you have all the required documents for that arrangement at hand?”
“Yes”
“I do not understand the question, could you rephrase it?”
(confidence intent detection Yes: 0.6638)