The unfortunate truth about All Clad is that they will only be new once. It sounds to me that, like a NORMAL COOK, you used salt in your recipe. The mind-blowing thing about All Clad products is that salt stains them and leads to white pits and discoloration. They recommend letting things come to a boil / simmer before salting, but the fact is, even heavily salted sausage will discolor a pan if seared.
I actually did a post on restoring an old All Clad piece with BKF that you can check out here
That said, the sooner you accept that your pans will only be new the first time you use them, the sooner you can begin enjoying their more positive attributes. They heat evenly, and with a little work, the outside will continue to sparkle for years. Ask any great chef what their favorite piece of cookware is. More times than not, it will be an unattractive piece that looks like hell but cooks beautifully.
Fwiw - I've not tried it, but my favorite corned beef in SF is from Guerra's. Very solid, artery pumped, delicious. Sadly, it outperformed even my home-corned brisket (also purchased from Guerra's).