I've been thinking why that tab broke. By the way, the new part has a 997 number so Porsche knew there was a problem. My alternator doesn't have a clutch, just a normal pulley. Starting to think that the stress of a clutchless pulley caused this failure. The new part looks a bit beefier.

 

Makes sense. With a plain pulley, the alternator gets extra stress whenever the engine slows down and slows down the alternator with it.