Unlinking Confluence space from JIRA Service Desk does not remove permission to access the space

Summary

When unlinking a Confluence space from a JIRA Service Desk via the Project Settings, (see Serving your customers with a knowledge base) JIRA Service Desk customers still have access to the space.

Before linking the space, the user was not able to view it and Not Permitted was displayed on the page.

Steps to Reproduce

1. Go to the Project Settings menu of a JIRA Service Desk project.
2. In the Knowledge Base tab, select Link to a Confluence space.
3. In the dropdown list displayed under Application, select your Confluence application.
4. In the new dropdown list displayed under Space, select the space you want to link.
5. Click on Link.
6. If you navigate to the space linked with a JIRA Service Desk customer account, you will be able to see the content of the space.
7. Go back to the Knowledge Base menu of the previous JIRA Service Desk.
8. Unlink the Confluence space.

Expected Results

After removing the link to the Confluence space, the user, logged in with a JIRA Service Desk customer account, should have Not Permitted displayed on the page when trying to access the Confluence space (where they were previously able to access the space via Service Desk)

Actual Results

The user still has access to the Confluence space.

Notes

Anonymous access is not activated.
Tried clearing cookies and reproduce the issue. User still has access to the Confluence space.

Workaround

Manually revoke/unlink the KB space from confluence
https://<siteURL>/wiki/spaces/spacepermissions.action?key=<spacekey>