Problem reponses report bug for Randomized Content block

I have a Randomized content block component that pulls 10 problems out of 20 problems from a library.
A learner saved 10 problems but when I generated a grade report for the unit I only saw 5 rows related to that learner.
I don’t know why, my guess is the report was generated based on a set of problems of mine, my set of problems unions with that learner’s set of problems resulting in 5 problems in common.

Does anyone have a similar issue?