Anyone else seeing Game Center forgetting records/ranking?

I finally got through Hard a couple of times with a decent score, which was gratifying. I went and checked in Game Center, and as with Easy/Normal I had my ranking, the score was saved there and the same as my record in the game, etc. However, sometime over the next day the entire thing vanished, and went back to showing me as "Not ranked", though the game itself still has my progress. This is kind of depressing after a long, good run. Is anyone else seeing this bug? Known issue?