You need to set the "response_mode" querystring parameter value for your links to tell Azure B2C how you want it to return both successful authentications and also errors back to your application. The valid values are "query", "form_post" and "fragment" and dictate how Azure returns when the user cancels. It looks like you have it either set to "fragment" or not set at all and it is defaulting to fragment.
From some of the Microsoft documentation:
response_mode - optional - Specifies the method that should be used to send the resulting token back to your app. Defaults to query for just an access token, but fragment if the request includes an id_token.