Hi Kylie Hocking,
Thank you for posting your question in the Microsoft Q&A forum.
After reviewing your question, it appears you're using the "Students edit their own copy" feature for files attached to assignments, and you're wondering whether students can still edit those files after the assignment has closed.
Based on my research, Microsoft does not explicitly mention whether file editing is restricted after the assignment due date. However, according to the official article Turn in an assignment in Microsoft Teams - Microsoft Support, and as you noted, the status of a student's submission may vary depending on your settings. If a student has not turned in the assignment, you should be able to identify this status as described in the article.
Regarding whether students can still edit files after turning in the assignment, it seems that they can, as noted in this post: If I turn in a word assignment on teams and edit it after as it is - Microsoft Community. Additionally, another post here: Why can students edit files in Assignments AFTER the close date? - Microsoft Community suggests that you may be able to view the edit history of the file even after the assignment has closed.
As a forum moderator, I rely solely on official Microsoft documentation so I cannot confirm whether post-deadline editing is a bug or an intended feature.
I hope the above information is helpful and gives you more clarity on this issue. If you have any further questions, please don’t hesitate to ask.
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