User B needs to verify their email for it to count. Otherwise you could enter a fake email and move up the list. When user B joins the list and verifies their email, A's internal score increases. The final list is sorted by score and then sign up date. So what you described is working as intended.

However, what you might be getting at is that you want a different sorting mechanism, which is a feature request. What would you expect to happen? Maybe I can consider that