I had exactly the same problem - in my case it was caused by the service worker loaded from flutter_bootstrap.js

_flutter.loader.load({ serviceWorkerSettings: { serviceWorkerVersion: "3554334882" }

If I comment this out then the app executes only once.

I am still in the process of figuring out whether it has any impact on the rest of the app - it looks like the service workers are still being created.l