I’ll dig around and see what my episodes look like. Do you remember the source (station ID or bug) yours are from?
Episode 1 appears to be from a pre-release screener; it looks the best.
Episodes 2, 5, 8, 10, 11, & 12 are from an unknown NBC HD station.
Episodes 3, 4, 6, & 13 are from NBC 4 HD.
Episodes 7 & 9 are from Global HD (Canada).