Strange Behavior with Quiz

We have uploaded Rise SCORM 1.2 packages to our LMS.  (We use Totara 12, which is a very old version of Totara.) Tracking is set to use the quiz result.

For the most part everything is working well but we have seen an odd thing in some cases.  A user gets to a quiz in the course and takes it but something seems to glitch while they are taking it, and at the end of it they get a display like what I've attached. The Quiz Results page is just blank and the continue button is not displayed.  The user cannot continue to the next lesson (which we have as a simple course completion message lesson) because the quiz is not passed.  When the user exits course to go back to our LMS, their progress is saved, but the progress is just frozen.  So if they go back in to try to restart the quiz, it just takes them back to the glitched screen.  It doesn't let them start the quiz over. The only solution I have is in my LMS to manually set that the user completed the course so they can move on with their training.

It also doesn't happen for every user on the same SCORM. In other words, I don't think there's anything wrong with the SCORM export.

I was able to get the "take again" button to display when the course results page is frozen by using the keyboard navigation and hitting tab.  so maybe this is the fix?

Any ideas about this behavior? Other ways to fix it?