I faced two questions. In fact, I submitted my ticket weeks ago but did not receive any reply from the support team.
(1) Once the students submitted their assignments, the grade is published automatically. The students are wondering and I need to delete the grade one-by-one.
(2) Once the students submitted their assignments, a few days later, the system will resubmit the assignment on the behalf of the students and considered as "late submission".
The following image summarised two items mentioned above.
Appreciate your help as I am unable to get the answer from the support team.
I'm not an expert, but these are two separate issues.
1) For assignments and quizzes for which you do not want the grade to be published automatically, use the drop down list on the title of that activity in the grades tab to select "grade posting policy." Set the policy to manual. If this applies to everything you can also access a grade posting policy for the entire course from the gear icon. As submissions come in, you will see crossed out eye icons appear next to the activity title and student name. The scores will be hidden from students, but not you. To post the scores use the drop down list next to the activity title to select post > graded. Be aware that if you ever click post > everyone even the blank boxes will be "posted" and scores will return to posting automatically, and the manual posting policy will become ineffective. In fact, if you (or any admin setting up your course) did selected post > everyone for an activity at any point previously, the manual posting policy will not work for that activity and every grade will be posted instantly.
2) It is not likely that canvas is submitting a duplicate of an assignment without some action by the students. The students may be resubmitting with slight changes, or else they may be concerned that they do not have a score for the assignment you are not finished grading and be resubmitting out of concern that they did something wrong the first time. If you are convinced the resubmission is from canvas without any action by the student, I would ask canvas support to identify the IP address of the "submission on the student's behalf" as compared to the original.
I am aware of item 1. However, my issue here is related to once the students submitted the file, the mark is captured automatically in which the file required manual marking. For item 2, students themselves said that they did not submit, but to their surprise, it was multiple submissions and in our assignment setting, we only allowed 1 attempt.
I would still check with canvas support to verify that the students are correct. If they are, it will be canvas support that needs to help anyway.
The only assignments that I have seen auto-submitting are quizzes. If a student stops before they submit a quiz for any reason, the quiz auto-submits (once) at the due time or when the time runs out for a timed quiz - whichever comes first. I have not noticed a quiz submitting twice for one attempt. Some of my students had a problem with the submit button that led some of them to state that they did not submit even though they had, but (I believe) that has been resolved