Somehow my iPhone was unlocked and not unlocked at the same time when I tapped on a iMessage notification from Philipp recently. No idea how that happened, but it seems like it should not happen. Imagine if Bob was able to tell Alice about that juicy Finder screenshot in our conversation that is now visible even thought my face was not recognized.
The right screenshot shows all the other notifications I had when it happened. I’m 100% certain that this is all there was, so I couldn’t have accidentally tapped something else (e.g. a banking app or anything that might trigger another FaceID scan after unlocking the phone itself).