[mdh]

I've narrowed this issue down a little bit more, and found another. On this one:
By blinking, I mean the clock either becomes wholly transparent if translucency effects are turned OFF, or the second digit of the seconds becomes garbled if translucency effects are turned ON. Also, the virtual desktop selector does not become garbled when translucency effects are OFF.
I've also narrowed it down to find that it only occurs when my cursor focus is in certain places, and even then, it's unreliable at best - oftentimes, typing in a text input box on a web form, or in the URL bar, will trigger it, but it's flaky about triggering.

The second issue I've found is that after opening several browser windows, progressive windows are painted entirely black - they still accept input, and become normal when sized down, but I prefer my browsers maximized. They still behave normally when they are entirely black (clicking the un-maximize button works, even, as do other non-WM parts of the window.) This impacts firefox, seamonkey, etc. I have not tested opening many of the same type of windows in other applications, so it's hard to tell if it's mozilla-specific, or even perhaps GTK-specific. I'll muck with this a bit today and see if I can narrow it down.