I've been recently working on these passcode pop-ups. Here is more detail about user scenarios down below.

Paier Vault® Scenario-1

After filling up your passcode, you can access your private zone. A highlighted OK button gives you a signal to take the next step. Also, the user won't be able to choose the QR code scan option because when you enter your pin, that means you are no longer need to try the QR method.

Paier Vault® Scenario-2

If you choose the QR code scan method to access your vault, the passcode area will be disappear and a QR code will come up. You can always go back to try your pin from the button at the top of the code. The yellow highlighted circle turns to proceed.