JIRA Issue Statistics gadget not working with trusted application link

Steps to reproduce :

Process 1 :

1. Start Confluence (5.2.3)
2. Set up trusted application link with JIRA (6.1.4)
3. Add external gadget - Issue Statistic gadget from JIRA to Confluence
4. Try to add the gadget to a page
5. The auto-complete would not work. Confluence is unable to pull data from JIRA

Process 2 :

1. Start Confluence (5.2.3)
2. Set up OAuth application link with JIRA (6.1.4)
3. Add external gadget - Issue Statistic gadget from JIRA to Confluence
4. Try to add the gadget to a page
5. The auto-complete would work fine.
6. Save the page
7. Now, remove the OAuth Application link and establish a Trusted application link
8. Go to the page with the gadget. The gadget displays an error :

   There are problems with the current configuration for this gadget. The errors below may have been caused by the deletion of entities required by the gadget or by changes to your permissions.

   • Invalid project