Why does my non-embedded app turn into an embedded app when blocking third-party cookies?

Technical Q&A
1

I’ve a Ruby on Rails app, built with shopify_app gem. It is a Non-embedded app(both in the app config and on the Shopify Partners dashboard settings for this app). However, upon app submission I received the following objection for this

We can confirm your app is unembedded, however upon blocking third-party cookies. It turns into an embedded app based on our recent screencast. Regardless of your app is originally an unembedded version. Your app should still work when blocking third-party cookies in Incognito.

I don’t know what I’m missing here which causes this behaviour. There is no tangible information that I could find to find the reason about this issue. This app DOES NOT USE APP BRIDGE.

Someone developer I reached out to said if I’m not using App Bridge then this can happen due to a redirect in my app, that sounds very counter-intuitive and unlikely, why would a redirect in my app(to my app’s route) cause it to suddenly become an embedded app?

Here is the config file

# config/initializers/shopify_app.rb

ShopifyApp.configure do |config|
  config.application_name = ENV.fetch('APP_NAME')
  config.api_key = ENV.fetch('SHOPIFY_API_KEY', '').presence || raise('Missing SHOPIFY_API_KEY')
  config.secret = ENV.fetch('SHOPIFY_API_SECRET', '').presence || raise('Missing SHOPIFY_API_SECRET')
  config.old_secret = ''
  config.scope = 'read_products,write_products,read_script_tags,write_script_tags,read_orders'
  config.embedded_app = false
  config.after_authenticate_job = false
  config.api_version = '2020-10'
  config.shop_session_repository = 'Shop'
  config.allow_jwt_authentication = true
  config.allow_cookie_authentication = true
  config.enable_same_site_none = Rails.env.production?
end