One of our faculty has created an assignment and set the max grade to 20 points. He started grading some of his students already. However, once he comes back again to grade, the max grade resets automatically to 100. I believe this has been reported as bug in Moodle 3.1 at https://tracker.moodle.org/browse/MDL-55520. But still we experience this bug at Moodle version 3.1.
Please let us know how to correct this. Our assignment is up to date on its version anyway.