When creating an assessment in the Assignment tool with an open date set in the future, If you select "Add due date to Schedule",
the assignment is viewable in the Calendar summary tool on the close date of the assignment - when viewing the Calendar summary tool from the course home page.
The assignment can be accessed by a student viewing the Calendar summary tool even though the assignment is not open to students as per the due date set in the assignment.
Attachments can be accessed and downloaded by the student in the Calendar summary tool entry for the assignment.
This issue related to https://jira.sakaiproject.org/browse/SAK-25303