We're doing some testing in beta related to pushing grades into an assignment.  We'll publish the assignment and then make it available.  Then we make a PUT query something like below.

/api/v1/courses/1677/assignments/78614/submissions/13627?submission[posted_grade]=21&access_token=XXXX

The token related to this call has full access to our instance.  

However, we often get the JSON response below

{"status":"unauthorized","errors":[{"message":"user not authorized to perform that action"}]}

This will sometimes fix itself overnight and allow us to put the grades in without changing anything about the query.

Has anyone encountered this?  Is there a reason time alone would move this from a "not authorized" query to one that works perfectly?