I am using the C# Google OAuth library.
I am not sure if this behaviour is expected, but a refresh token is not being set in the TokenResponse file if GoogleAuthorizationCodeFlow is called for an app that has already been authorized.
I am using the Search Console API - so want to use a different TokenResponse file for each site for which I want to get data from, but on setting up the 2nd, 3rd, 4th etc sites (I am using site id as the user id in AppFlowMetadata GetUserId) the TokenFile is created without a refresh token.