Captcha doesn't appear when adding a comment

Preconditions: Have a page created with Comment rights for Unregistered users.

Steps to reproduce:

1. Access Administer Wiki
2. Click on Other > CAPTCHA
3. Select Type > Text / Image / Sound
4. Select one of the Engine
5. Click on the Save button
6. Click on Users & Rights > Rights
7. Tick "Require unregistered users to solve a CAPTCHA when posting a comment on a page"
8. Log out of the wiki
9. Access the page with Comment rights as an unregistered user
10. Add a comment

Expected results: The CAPTCHA appears once text in added in the text box.

Actual results: No CAPTCHA appears.

Note: Captcha appears in 12.6.2