Billy Crudup's character says that St. Bernadette is Our Lady of Lourdes. Lourdes is where St. Bernadette had her visions, which were of Our Lady of Lourdes (Mary). The two are not equivalent.
Around 36m 30s, the rear window of Bernadette's car is missing.
During the YouTube video of Bernadette's architectural career, the narrator states that concrete for the 20 Mile House came from nearby "Gardenia." The name of the city is Gardena; it has three syllables, and it's pronounced with a hard "N" before the final A.
During the YouTube video of Bernadette's architectural career, the narrator incorrectly says the name of architect Renzo Piano as Lorenzo Piano.