If one uploads a feedback file for a student, this is saved; but if one returns to upload a second feedback file for that student later, the first uploaded feedback file disappears /is not shown. The only way to upload two files, is to do so concurrently, while in the same session at the 'submit feedback' page.

Previously typed feedback text to the student in the TinyMCE html editor, also disappears unexpectedly.

This bug is described with error messages in the following support thread:

http://moodle.org/mod/forum/discuss.php?d=210689