Here's one thing to try (as root):

Code:

gtk-update-icon-cache -f /usr/share/icons/hicolor

(Ooops, see below, please)

It could just be the pixmap cache is corrupted, in which case this should recover it. If it's not the pixmap cache, then it seems like the filesystem is indeed getting corrupted. Not at all sure how, but if this is happening after a clean flash in a new device, and not happening to anyone else, it sounds like the root is a hardware fault.

No, I'm an idiot; actually the above code won't help, because the gtk theme pixmaps are stored separately from icons, and I'm not seeing a cache for them here -- I think they're only cached by the sapwood server, maybe. So I'm not seeing an obvious solution other than warranty service.