That’s interesting to know. My Maestro cards don’t have a XXXX-XXXX-XXXX-XXXX number at all. Does yours?
See for example this page, which says that “You cannot use your V PAY or Maestro card to make online payments. If you want to shop online, you will need a credit card or prepaid card […]” https://www.ubs.com/microsites/hilfe/en/debitcard/online-payment.html