It seems Shopify has fixed the issue. Deep linking is working fine now.

The docs - https://shopify.dev/docs/apps/build/online-store/theme-app-extensions/configuration#app-embed-block-deep-link-url-query-parameterstell to use api-key instead of SHOPIFY_THEME_APP_EXTENSION_ID. 

Hi Shopify Community, I’m currently developing an app that includes an App Embed theme extension. I’ve followed the steps provided in Shopify’s documentation for creating a deep link. The deep link I’ve created is in this format:https://<myshopifyDom...