Score tracking issues when using "Draw from question bank"

Hello,

Today we  have come across one more issue. Not sure if anyone has already came across this issue but I could not find anything on this forum. 

We are using the "Draw from question bank" feature to display our random questions. The feature works fine but  the issues comes up when the user exits the quiz  halfway and come back to resume the quiz.

Our quiz has 20 questions. User starts the quiz and finishes few questions. Lets say the user finished 8 question scoring 40% marks. Then the user exits the quiz and comes back to finish the quiz.

This time it starts with 9th question and then finishes the quiz with all correct answers for remaining 12 question. However the final score recorded is 60% instead of 100%.

On the first attempt the LMS recorded the score of 40%. So we we were hoping that storyline will just pick up the existing score and add the new score to it from the remaining questions. Does it not how it suppose to work?

We also tested this scenario but not using the "Draw from question bank" and it works perfectly fine.

Can someone please advise if this is a  bug or is this how it is suppose to work.?  

If needed we can post the story files of both versions.

Please advise.

Thanks