Yes, but that doesn't find the missing entries; the smart playlist will only recognize a few mastered games automatically, the rest I have to manually select in the all games view and let the metadata load, then selecting the mastered games smart playlist and it will update and display correctly. Scanning all games for achievements will actually remove the manually selected games, it's as if some data about the achievements is missing or doesn't get pulled during the scan, but the local achievement metadata, when loaded, will fill it in?
This specifically is a very minor issue for me and can live without this playlist, but I wonder why it's happening and if my other smart playlists are missing entries as well.
edit: clarifications and additional info