We are experiencing the same bug as mentioned here: https://moodle.org/mod/forum/discuss.php?d=434465
It directs to https://tracker.moodle.org/browse/MDL-74752 which still seems not fixed.
I couldn't find any progress on this?
What basically happens:
- Students take a Quiz
- Teacher discovers an error in a question
- Teacher fixes the question
- Regrade is being aborted with an error
So how to fix this?