Problem on questions after update coursepress

Hi after i update i notice that i have some problems in some Questions on my courses.
On my courses i decided to present the content divided in lessons, then on the penultimate lesson i made a Quiz and on the last lesson i have created a way to generate a certificate to the user.

One of my users that had already completed a course, logged in and could not access the Certificate lesson to regenerate his Certificate, cause the quiz lesson keep saying that one of the questions were not completed.

But he had already completed that Course, so for now i have identified that this problem was on Checkbox Questions(Multiple Answers). I remove his answers from those questions and ask him to fill again and it worked.

I dont know exactly where is the problem but it looks that sometimes the registered answers to the questions on my Quiz disappear and this is causing a problem to users.