I did some research and it looks like a bug in the mobile app. It works in any browser on computers. It even works on mobile devices when using the browser access and not the app. If I set new metafields for a product in the categories that don't work in the app I can't even see them being updated now. The store filters without any problems, even though the mobile app shows nothing. In the browser I see everything as it is with set metafields.
Shopify Support has been notified to confirm this.