...
With regards to having the post date set before the due date. This is a feature which has been introduced by design, as it gives the ability for instructors to provide feedback to students who have submitted an assignment, perhaps a first draft. This will allow students to view initial feedback, continue to progress with their assignment and resubmit their assignment until the final due date. This feature is available in submit.ac.uk and is therefore available in all LMS’/ VLE's
Allowing Pop-Ups
When launching the document viewer or submitting work, both staff and students will need to allow pop-ups. This only needs to be done once per browser, and the setting should be retained unless you remove it. Instructions on Disabling Pop-up Blockers for different browsers can be found in our Student E-Learning Support guides.
Issues Turnitin are aware of and we are awaiting a fix
...