I am currently working on a custom integration using the Storefront API to sell community merchandise and digital perks directly from an external gaming resource website. Everything functions properly on desktop browsers, but several mobile users running webview sessions report that the checkout redirect randomly strips cart attributes and drops the customer session before reaching the Shopify checkout screen.
I suspect the problem is related to third-party cookie restrictions and cross-domain tracking policies when passing parameters between our client environment and Shopify. Has anyone dealt with persistent checkout token drops across independent subdomains, and what is the best practice to ensure the cart state smoothly handoffs without triggering CORS or authentication resets?
I also outlined the integration flow on our website in case it helps others compare the expected handoff behavior.