Can't get checkout consent sync to work

[z0n]

Hi, I'm running Hydrogen 2026.4.2 (including this fix) on Oxygen and I'm trying to get consent sync to run. I followed this guide to integrate Cookiebot and it seems like it's working. I can see some cookies being written (e.g. _shopify_analytics/_shopify_y/_shopify_s), although no _tracking_consent but that seems to be disabled when backend consent sync is used (= forced since 2026.4.0?).

For some reason though, the consent never reaches the checkout.
I'd like to understand how exactly it's supposed to work as I see there are a few different ways to transfer consent (_cs cookie in checkout URL, _tracking_consent cookie, ???).

We have a bit of a non-default setup:

• Cloudflare in front of Storefront with different store domains for different countries (using one Hydrogen deployment in one Shopify store)
• Custom cart implementation which runs through a different API but uses the original Shopify cart underneath

This makes a reproducible setup a bit difficult, that's why I'd like to understand how exactly the consent transfer is supposed to work. Maybe we're not passing something in an important place or something like that.

[z0n]

Just downgraded to 2026.1.4 to see if it works with the legacy consent sync and it works out of the box. So we're having some kind of issue with the new backend consent sync.

[z0n]

Update: I got it working now. Our custom cart implementation didn't forward all the cookies to the Shopify API. Once we fixed that, the backend consent sync started working 🎉