Offline token is gone when refreshing the page

We have a web client (Angular) that we need to use offline access for that user (infinite connection to a data board)

we init the adapter with

          checkLoginIframe: true,
          onLoad: 'check-sso'

And when calling login, we set the scope to be openid offline_access

Once the user logged in, we get an offline session with an offline refresh token.
If we refresh the page, the next token that we will get is a regular token, not an offline one, that has expirations.

Is it a bug? anything I’m missing here?