Penn seems historically rough for URMs according to myLSN. I mean, with a 3.5/163, you are still below both medians and Penn isn't exactly known for being holistic. If anything, they're one of the major hard numbers T14s, which is probably why they YP more than almost another school save Michigan and UVA.
Still, with such a limited number of AAs to go around a straight up ding is really weird. Any glaring weaknesses - bad LOR, unexplained gaps in resume or education, C&F issues - could've done the trick. Though if that were the case Berkeley, GULC, or Michigan would've picked it up as well I would think.
Tough break. Hopefully the rest of your cycle goes well.
163 is old score. High 160s now. I guess I'll just have to see how the rest of the cycle plays out.