How to reproduce:

Create an RSVP
Set:

  • Display Guest List: "Hide Guest List"
  • Detail Level: "Hide Invitees"
  • Display Guest List Inside Event/Node: "Hide"
  • Guest List View Permissions: Uncheck all roles

Now, invite an anon user to the RSVP by email address

When the anon user views the RSVP, they will still see a Guest List section with some information about the invite.