When an assignment is marked as do not include in final grade in Canvas, that information is not sent to PowerSchool and the assignment is included in the final grade. Attempts to change the assignment to not included in the final grade in PowerSchool are overwritten every time grades sync.
It makes sense to include the "do not include in final grade" in both systems. OR if an assignment is marked do not include in final grade in Canvas, do not allow a teacher to include the assignment in the grade sync. I will be answering questions about this all year, wasting huge amounts of time.