Assign Vendor Items - Column Headings Sorting is not working

When clicking on the column headers on the Assign Vendor Items, the sorting does not appear to be working correctly.

For example, clicking on the Distributor Heading appears to sort the data based on the values in the Name column.....

• On page load
  • 
• Click on Distributor, once, and then again!
  • 
  • Data is sorted by Name....
• Click on Distributor again
  • 

Please check all columns and make sure that if sorting is enabled, that it is sorting correctly.
Thanks