Brightspace/Turnitin error: You must supply an author user id when submitting as instructor.

We are currently experiencing issues with the Brightspace-Turnitin integration, which is causing submissions to not be transferred to Turnitin from Brightspace under certain conditions. If a Brightspace Assignment is created, but Turnitin has not been enabled and submissions have been made to the Assignment, enabling Turnitin will cause submissions made to the Assignment to show an error. Submissions made after Turnitin has been enabled will be processed correctly. The supplier is currently looking into the issue.