Language on merchant terminal changes when paying with iphone

When I use my iphone to pay in a store, the payment terminal of the merchant will switch from Dutch to French to inform me about the progress of the payment. This has been happening for a week or so. I have not changed anything in my settings and I did not get a new debit card from my bank. It’s a Dutch card from a Dutch bank and it has been working fine for years. Language and region settings on my iphone are still set to Dutch and Netherlands.