Shopify Markets switches to wrong product page

[JWDMK]

We are trying to get our first Shopify markets store live. The original store is in English but we now want to add French. We picked a fr.suitsuit.com domain structure (since this is the same structure we have for our other non-market stores (nl.suitsuit.com and de.suitsuit.com). When you visit fr.suitsuit.com the store is in French. When you click on "boutique" to start shopping the collection page has the same and correct domain structure https://fr.suitsuit.com/collections/fab-seventies-all however, when you try to visit a product it switches to the www.suitsuit.com domain and to English, see for example: https://www.suitsuit.com/products/fab-seventies-red-ochre-carry-on-20-inch if you switch to French then it remains in the same domain but to: https://www.suitsuit.com/fr/products/fab-seventies-red-ochre-cabine-55-cm (so .com/fr) instead of the  https://fr.suitsuit.com/products/fab-seventies-red-ochre-cabine-55-cm which is available too.. Any ideas why it leaves the fr.suitsuit.com domain after visiting the PDP?