The Bavarian State Opera has announced its 2006-07 season. Ordinarily, that’s not the kind of item that would make headlines in America, but a few sharp-eyed journalists have noticed that the company has booked Placido Domingo to sing the lead in Parsifal next spring, on the same dates that the Washington National Opera has engaged him to sing the lead in Die Walküre. No one has yet explained how the mistake occurred, or which company will actually have Domingo on its stage when all is said and done.