Before raising this tracker issue we installed a clean Moodle 3.9.6+ (Build: 20210416) and confirmed the issue still exists.
Tested initially on moodle versions 3.9.4+ & 3.10
Reason we tested on these versions is because we are aware of fixes
that were applied to moodles from version 3.8.5 and 3.9.2 and we think this issue might be associated with those fixes.
Configure assignment for 'Scale' grading and 'Student Upload Files' and 'allow manual re-attempts'
Student submits assignment, the marker then provides 'feedback comments', does not select a scale grade, and selects 'allow new attempt'.
Student then revisits the assignment and is able to see that they could make a new submission, but they do NOT see the markers feedback comments for the initial submission.
If the student visits their gradebook page, they are able to see the markers feedback comments.
Repeat the scenario but when grading, do NOT reopen the assignment to allow the student to make a new submission. Outcome = Student does see the feedback on the assignment page and in the gradebook.
Note: When using percentage marking and reopening the assignment to make a new submission the student does see the graders feedback.