QR Code Scan triggers next Code, even if already submitted

How to reproduce:

• A voter scans a QR code, but does not immediately access the URL.
• The Manager clicks submit to generate a new QR code
• The next Voter wants to scan the QR code
• previous Votes now opens the URL and the currently next QR code is not anymore shown

Problem: The QR Code generated in the meantime is not used.