Login challenge for private ideas link when not logged in

When a partner portal user receives an update email and clicks the direct link for a private idea in a portal, the user gets a message saying "The record you are looking for does not exist..." if that user is not already logged in.

The message is misleading the user into thinking the idea has been deleted.

A much better outcome would be to have a login challenge for the user and then, upon successful login, direct the user to the desired idea.