[Building Sakai] Assignment tool: Problems with grading

[RAUL SANCHEZ VEGAS]

Hi

We are experimenting problems with the Assignment tool:

Previous facts: There is an assignment associated to a Gradebook2 item 
which has been created before the assignment. The assignment has one 
student submission:

1. The Instructor grades student in the Gradebook2 item with 6 points.
2. The Instructor grades student in the assignment with 7 points and 
clicks "Save", however the 7 points are not stored, and remain the 6 points.

The instructor is not allowed to change the student's score in the 
assignment because the Gradebook2 item that is associated to the 
assignment, has already a score.

We have Sakai 2.7.2 and Gradebook2 1.8.0.

Is there any solution?

Thanks,
Raúl