Steps to reproduce the issue

Install a clean staging.
Create an article set to registered with a Read More and set Show Unauthorised Links to Yes.
Create a menu item to display that article and set Show Unauthorised Links to Yes.
Create a Login Menu item which will display on the same page as the single article menu item.
Add a login redirection to that login menu item to anything else that the single article menu item created above.
Display the article in frontend.
Click on the "Register to Read More..."

Expected result

After login, it is expected to be redirected to the full article.

Actual result

One is redirected to the redirection set in the Login Menu item

System information (as much as possible)

Additional comments

This happens on mono as well as multilingual sites.