I came upon this discussion: https://moodle.org/mod/forum/discuss.php?d=367028 and I could not find a tracker created accordingly.
However, I have suggestion for this. In the grading screen, you have this:
You can see the 'allow another attempt' selection right below.
How about adding a 'Lock submission' option there as well?
I also have noticed students changing their work after it has been graded. And we need to have a copy of the graded work (by law). But students can delete and resubmit (even if you only give them one attempt)
So... should I create a tracker for this?