User blog comment:Kajune/Lucifer, first son?/@comment-3045936-20160408061200/@comment-34326521-20160408061728

That's why it's a retcon - because it changed established continuity. This is exactly what happened with Reapers, remember? One character who should know better made a small, seemingly contradictory, comment on-screen (Dean, regarding Tessa), and it turned out to be a retcon. In this case, it was Amara who made that comment, and she was actually there to witness it.