"Print Date" drop down in certificate settings screen does not list all the quizzes expected. I had a look at the code and I think the problem is in certificate/mod_form.php at line number: 88. At this line it unions 2 arrays, dateoptions array (values: "No"(id=0), "Date Issued"(id=1) and "Course Completion"(id=2)) and coursemodules array. In my particular case, I have a quiz with id 1 and its course module id is 2. So when it unions the array the id "2" is taken from the left hand side i.e. ("Course Completion") hence the quiz with coursemodule id = 2 is not populated in the dropdown.

If this issue gets fixed, the "certificate_get_date" function in mod/certificate/lib.php also needs to be fixed.