LTI 1.3/Advantage 409 Conflict when updating line item before sending scores

Although the LTI specs do mention that the timestamps sent for the scores must not conflict (https://www.imsglobal.org/spec/lti-ags/v2p0#timestamp), it is not clear to me why the timestamp at which the line item is updated can conflict with scores published.

To Reproduce:

1. Create a new line item (existing one should work as well)
2. Update the line item's scoreMaximum
3. Send scores over for at least one user with a timestamp before the timestamp at which Step 2 occurred
4. See 409

I've also included a video of the issue: https://drive.google.com/file/d/1BQVhG4BWLgLc8RdBXk63AeiuJMjUXmPQ/view?usp=sharing

I expected to not run into a 409 just because my scores had a timestamp older than the time at which I updated the line item. 

I can work around this issue by sending the current time for every score post, however, I'd prefer to be able to send the time at which the submission was graded.