Race condition in registration approve + save

One-sentence description

I'm not able to register a payment for an automatically approved registration of membership.

Current behaviour / Reproducing the bug

1. Somebody registers as a member for Thalia and completes all steps
2. Approve registration
3. Save registration within a couple of seconds
4. There is no button for payment
5. I hit the 're-evaluate' button and again approve the registration
6. Now there are buttons

Expected behaviour

Buttons immediately, or members not being approved automatically