Looking at the code, I do notice a difference between the completed state of a submission at the collection level (e.g. the “JAVA” collection) vs leaf level (actual assignment, e.g. “Hamming Distance” in the “JAVA” collection).

A submission is marked as completed when the student hit the submit button. This flag gets reset when re-opening his submission.
However, the completed flag at the collection level will be set to true only when the child submissions meet the PASS criteria. This inconsistent semantics is definitely confusing. I’ll look for ways to improve this for upcoming release.

Submitted by Elmer van Chastelet on 8 March 2019 at 13:37

This is incorrect. Completed is set to true for collections, when at least n sub-assignments are completed where n meets the collection pass criteria (pass-all, or n-of-m)