1. Go to Reports > Performance > Top Marks
  2. Clear Team filter, then select other desired options and Create Report

If issue still exists then
  1. Go to Set-up > Groups/Subgroups/Codes
  2. Check for Codes with a Type but no Code or Description - highlight one and click on Delete in top bar.
  3. Repeat as needed
  4. Then go to Reports > Performance > Top Marks, clear Team filter, select other desired options and Create Report