Multilanguage Product Title in Checkout: bug?

[Maksimsk]

Hello,

I am working on a headless Shopify shop with a separate storefront which gets the products through the Buy SDK. I have also set product titles in four languages (en, de, it, fr) through the GraphQL API. If I'm going through the Shopify Storefront everything works correctly as expected -> PDP and other pages including chekout page are shown in chosen language and product titles are being translated. Though when going from the different storefront to the Shopify checkout, we are giving a url parameter, i.e. "?locale=de" to trigger the checkout in the language the customer has chosen in that storefront. And everything works but product titles. 
BUT: when I manupulate the URL param to a different language, i.e. "?locale=fr" it works. And if I then go back to the "?locale=de" it also works! So it doesn't work initially, when we need it at most. 

Does someone know if it is a bug or am I doing something wrong?

Referenced Shop: https://www.boards-more.com/de/ion/bike

Kind regards,
Maksims Kuznecovs

[Maksimsk · Accepted solution]

Hey, if someone is interested, I've got an answer from Shopify to this topic:

Instead of using the locale parameter to translate your checkouts, you'll want to use the @inContext directive instead in your Storefront API requests. Here is more information on creating a checkout in the customer's language.