Ways for RER A are inverted.
/destinations/rers/a says Way A is Marne-la-Vallee Chessy / Boissy-Saint-Leger and Way R is Cergy-Le-Haut / Poissy / Saint-Germain-en-Laye.
But you get the opposite when checking the schedule :
/schedules/rers/a/auber/A says Way A is Cergy-Le-Haut / Poissy / Saint-Germain-en-Laye and Way R is Marne-la-Vallee Chessy / Boissy-Saint-Leger.
Ways for RER A are inverted. /destinations/rers/a says Way A is Marne-la-Vallee Chessy / Boissy-Saint-Leger and Way R is Cergy-Le-Haut / Poissy / Saint-Germain-en-Laye. But you get the opposite when checking the schedule : /schedules/rers/a/auber/A says Way A is Cergy-Le-Haut / Poissy / Saint-Germain-en-Laye and Way R is Marne-la-Vallee Chessy / Boissy-Saint-Leger.