Blurry/pixelated icons at random in Finder windows

Just upgraded my MBP (C2D, 3GB RAM) to SL, went smoothly. I'm seeing a lot of blurry icons in the Finder, though, seemingly at random. I'll open a window and about half the icons will be essentially large versions of the 16x16 icon, rather than sharp icons at the appropriate size. Changing the icon size via the new slider just enlarges the blurry icon, it doesn't increase the resolution.

It goes without saying that I'm seeing this on programs, files, and folders for which high-resolution icons is available.

I haven't seen this mentioned elsewhere. Is it a common problem? Surely it'll be addressed in a forthcoming update, but I wonder how rare it is. The only oddball thing about my system is that I have an older ADC-connected 23" Apple Cinema Display monitor connected to the DVI port via Apple's behemoth of a DVI->ADC adapter.

Thanks,
Eric.