Steps to Reproduce:

1. Order a JQL search results by a custom field's name. For example:

   ORDER BY "Custom Field" DESC
   

2. Click on the 'Custom Field' column to re-order the results.

Expected Results:
The JQL search would be updated to:

ORDER BY "Custom Field" ASC

Actual Results:
JIRA adds a new ORDER BY sort using the custom field ID rather than updating the one using the custom field's name. This causes the search to fail and an error to be displayed on the screen stating the custom field is used multiple times in the JQL (see attached screenshots):

ORDER BY cf[10000] ASC, "Custom Field" DESC