I'm an app developer, just about to send my app for approval, but I want to fix this issue first...
I cannot seem to find anyone else online who has had this issue.
Whenever the app is opened in the Shopify Admin Dashboard the Shopify Admin Dashboard briefly disappears, and my app appears full-screen, then my app disappears, the Shopify UI re-appears and my app appears inside the UI as it should be.
My app was setup using the Shopify CLI. It is a node app.
I assume there is some weirdness with the initial configuration that the Shopify CLI setup? Possible a Next.js issue?