Several references are made to various nuns service in monasteries. Nuns serve in convents.
(at around 19 mins) Sister Sarah drives with no key in the ignition and in the off position.
Sarah is shot on left hip during gunfire between her and Father Carlito. The wound disappears in the next scene.
When the station wagon family stops at the gas station, Rigo yanks open the hood, puts his hands on the radiator and looks around the engine. The radiator would be searing hot on a drive thru the desert.
When Sister Sarah pulls into Butch's, the motel has no exterior lighting and half of the roof is damaged, bent or missing.
When Chavo visits Mother Magda, Father Carlito's dead body is breathing.
Instead of torturing Sister Mary, who had taken a vow of silence, they could have just asked her to write down what she saw.