Buy it now - values are passing through the Checkout API but not showing on Checkout page

[Advisma]

Before the Shopify update, I could always transfer the values of my entries with "Buy it now" to the checkout via the checkout API.

Now this is no longer possible on OS 1.0 and OS 2.0.

Do you have a solution for this?

1. Here you can see my entered values and the I clicked "Buy it now"


2. Here you can see checkout API is getting my values but nothing is shown in checkout.


Explanation:
https://www.loom.com/share/90636a2ba86a410098b94367527d3e80