You want to know why the URL of one of your environments is displayed when searching for your app via Google. This article provides information about this behavior.
A website is shown in Google's search results after it has been indexed. A page is indexed by Google if it has been visited by the Google crawler ("Googlebot"), analyzed for content and meaning, and stored in the Google index.
It is difficult to know the source of Google indexing. For example, Google can index a URL if it gets its link from any other page it is indexing. You can prevent Google or other search providers from indexing the URLs by explicitly adding headers/meta tags to the web pages.
Refer to Block Search indexing with noindex for more information on how this can be achieved. Please note that this may take many days to take effect until currently indexed pages are removed from the Google cache.