Info not saving in Google Classroom

I received this message from a parent: "We’ve noticed that sometimes John will turn something in on Kami, but it will not show all of his work. He ends up having to go back in, unsubmitting, and then resubmitting. Any tips to ensure all of his work will be there when he turns it in?

Any suggestions?

This happening in my district as well. The Technology person suggested students save their documents via kami and then submit that file. I am not sure why this happens but it is difficult to find answers. I am unsure if it is the teacher posting error, the students submission error or a kami bug.

Let me know if anyone figures this out.