When allowing students to view a rubric before they submit an assignment the student must go through the Navigation > Submissions grading to view the Rubrics.
1) Create an assignment with a Rubric. Make sure you check the box for 'Allow users to preview rubric used in the module (otherwise rubric will only become visible after grading)'
2) Log into site as a student
3) Click on the assignment with the Rubric
4) Notice no preview of Rubrics available
5) Go to Navigation block
6) Below the assignments name is a link for 'Submissions grading'. Click on submissions grading and you will see a preview of the Rubric.
Enhancement would be nice if student could preview the Rubric on the actual assignment page, as soon as the click on the assignment link. Navigating to the 'submissions grading' does not seem to be intuitive.