To reproduce the problem:
1.- Inside some course, created a resource of the type "assigment"
2.- Define the values of the assignment (name, description, availability, delivery configuration, notices, grade and other adjustments).
3.- Once the task has been created in the course, access as a student and perform a delivery in this assignment.
4.- Enter as administrator or course teacher, go to the task and change the description of the task. Save and return to course.
5. Enter task settings, and check that the value "Max Score" has changed.
I attach screenshots of the before and after values in the "assignment" module grade settings.