In the review phase students cannot download the PDF file that was submitted by another student in the submission phase. When clicking on the PDF file for downloading, they receive the error message:
Sorry the requested file could not be found

With debug mode enable, the message is:
Error code: filenotfound

Stack trace:
line 463 of /lib/setuplib.php: moodle_exception thrown
line 1774 of /lib/filelib.php: call to print_error()
line 4443 of /lib/filelib.php: call to send_file_not_found()
line 37 of /pluginfile.php: call to file_pluginfile() 2.9