Hi Benjamin,
I’ve looked into this a bit further and I think this might actually be potentially expected behaviour, based on what I mentioned above with the App URL being replaced with a temporary tunnel URL when running the app dev command.
I have confirmed with our team internally that the new app dev command functionality does also include Proxy URLs in the url’s replaced with a temporary tunnel url, when the app config has the automatically_update_urls_on_dev flag set to true, or when it’s not specified in the config toml file, the Shopify CLI will prompt you to ask if it should replace the URLs or not.
More info here:
I would recommend confirming that your app toml configuration has automatically_update_urls_on_dev set to false and that you clear your last dev environment with the shopify app dev clean command to remove any temporary urls that were set this way.
If the behaviour is still happening on your development store after clearing this and ensuring the URL’s aren’t automatically updated when running app dev, or if it is happening on a production store, not a development store, then I would still recommend reaching out to Shopify Support as mentioned above and we can help look into it further.