When describing the visuals documenting the flows, there is a step that includes “The user authenticates to the authorization server”. In each case this should include verbiage to indicate that this is only necessary if the user is unauthenticated, e.g. “If unauthenticated, the user authenticates to the authorization server…”. Specific sections include 3.1.1, 3.1.2, 4.1.1, 4.1.2
Feedback from Dean Saxe on WGLC
https://mailarchive.ietf.org/arch/msg/oauth/T9XDSCqvVWPQAjDHjkH9iOQXsOo/