PowerSchool Grades Pass-back Update / Best Practice as of 6/25/2020:

Keep Titles Simple - Your assignment or Quiz CANNOT have a name longer than 30 characters.
Your Assignment or Quiz MUST have a due date.
The due date MUST be the same for everyone if assigned to everyone.
The due date MUST be a school day in PowerSchool within that quarter.
The due date CAN differ if assigned to different sections (entire sections only).
The due date CAN NOT be different for each student or groups of students
If you do not uncheck Post to SIS, then the next time you post grade it will continue to overwrite that assignment each time. It is a good habit to uncheck all assignment syncs once the sync has completed. Canvas assignments will lock after a quarter has completed. Note if you post grades again and changes you made on PS side will be overwritten by the newest Canvas posting so turning the assignment off is good practice so that changes will not be overwritten.
If your grades do not post or update in PowerSchool, check the grade sync page for possible errors. Grade Category error means that you need to revisit this page. If an assignment is created in PS but is blank try deleting it in PowerSchool and pushing from Canvas.