Our own postal code on checkout for customer

[emile_rdam]

We have a weird issue. A few customers complained that when they do the checkout  (standard Magento 2.3.3p1) that they fill in al their details on /checkout/#shipping  . All good

Now they go to /checkout/#payment

Then some customers will not see their own address but they will see the postal address from our shop (3053JD).

We had several calls and e-mails so we are sure it exists. But we can not reproduce ourselves so far on any browser. Nothing in /log or reports.

So not sure how to fix. You can try on https://fietskinderzitjes.com/