Anchor link is not past after login

Summary of The Bug

An anchor links that redirect user from an unrestricted page to the restricted page will redirect user to the login page if the user have not login to Confluence yet.
Login URL is like this

http://localhost:8346/testingpath/login.action?os_destination=/display/Bounce/CSP-xxxxx#CSP-xxxxx-however

As stated there, the expected behavior that Confluence should take is redirect the user after login. However, although Confluence do redirect the user to the requested page, the anchor link is deleted.
Here is the URL after login.

http://localhost:8346/testingpath/display/Bounce/CSP-xxxxx

Steps to reproduce

1. Set anonymous access on the Global level and Space level on the test instance
2. Create anchor link in Page A
3. Set view restriction for Page A so that anonymous user can't access it
4. Create Page B with the following wiki markup

   [Anchor link|http://<Server Base URL>/display/<Page A space Key>/"PageAtitle"#"PageAtitle"-"anchorname"]
   

5. Set view permission for Page B so that anonymous user can access it
6. Logout
7. Access Page B, and click on the Anchor link
8. Login

Affected version

Confluence version	Result
3.1
3.2
3.3
3.4.6
3.4.9