There is a known issue with Turnitin submissions being incorrectly marked as late within the Canvas grade book when using the LTI API plugin. Grades may be shaded in pink and submissions marked as late even if the papers were submitted on time.
Our integrations team is aware of this issue and are working with Canvas to improve the plugin, but there is no immediate fix for the issue. We apologize for any inconvenience this may cause.
Note: Turnitin records the exact date and time a paper is submitted. This can be found by opening the Originality Report and clicking the information "(i)" symbol located toward the bottom left of the Document Viewer page. This will give the time stamp for the paper and provide other information.