OpenCart 2.1.0.1 - Reward points not deducted

Hi guys,
I am facing some trouble in 2.1. When a customer buys something with reward points they do not get deducted from customer's account. So they repeatably purchase with the same points.

To avoid any misunderstanding I tested this on a clean fresh OpenCart 2.1.0.1 install.

Did anybody face the same problem?

I found the answer after tons of debugging.
IT IS A CORE BUG in Open Cart 2.1.0.1 !

I implemented the solution in my module flexi reward points so store owners are safe to use reward points on 2.1.0.1 with it.
http://www.opencart.com/index.php?route ... d%20points

Kind regards