Figured out the fix that worked for me. Hopefully this helps others that may have this issue.
From one of the courses that worked I identified that the php uses id=(whatever) so I knew that a specific course had a specific ID. I then went to another part of the gradebook like "user report" or something else from the drop down other than grader report. You then change out the ID in address bar appropriately to reflect the other id (the broken ID)
This was my temporary workaround, I then dived in a bit further. In the drop-down menu you will see "My preferences: Grader report" --> Select this.
On this page scroll down to general and in my case I adjusted the "Students per page" variable. Once I downsized that it cleared the 500 error.
Trial by error/fire. Gotta love it! If at first you don't succeed, try, try, try again. (William Edward Hickson)