tl;dr: Tesla first said it's "normal degradation". I threw an undignified hissy fit, then quickly apologized, but the rep did have them double check and found a mistake in their first check and indeed I have a flaw in the battery pack that they're going to address.
Longer explanation:
I got a text saying the car was ready for pick up. Tesla looked at the battery while I had the car in for it's 62,500 mile maintenance (a little early, I'm at 61,500). They said the battery showed no faults and that I should understand that there will be degradation over time.
I typically make an extra effort to be nice to service folks, at any business, it's hard job, and I'm feeling a bit abashed at the moment because I completely f**cking lost it at the fellow on the phone, who was just the guy that answered when I called to ask what the outcome of the battery investigation was. The service rep handled my tantrum gracefully. I apologized, but said I want to speak to the manager because if this is normal then I have the worst "normal" degradation of any P85 owner I've ever heard of. He said he'd look into it and have someone call me, hopefully that day.
Followup 2:
Chris (the same fellow I threw the tantrum on) called me maybe 45 minutes later. He started poking into it and says that when they pulled the logs, they pulled it on the wrong car. They just pulled the logs on my car and "one of the bricks has a bad SOC" or something close to that. They're going to send the battery to remanufacture once they can source a loaner pack for me. I'll pick up the car tomorrow and drive it until a loaner pack becomes available.
I'm slightly skeptical that they really did pull the wrong log and I wonder if it was checked at all the first time around, but I'll give the benefit of the doubt on that. They just moved the SC a couple weeks ago and the entire staff was in Fremont for training a week or so ago, so things are really crazy at the moment as they catch up.