dose this sound like your issue? http://support.apple.com/kb/TS4440
We've actually seen this issue come up from time to time in our Mountain Lion image. Its not very consistent. Most times I've imaged test Macs I haven't seen it, but some of the people I work with have, and have shown it to me. As described, just relaunching Finder or sometimes opening another app fixes it.
The article from Apple doesn't even explain what the issue is, which is pretty lame if you ask me. Basically just a standard "reboot' answer, but doesn't address what the actual issue is.
Although its not consistent, and not very serious, it would be great to eliminate it from our image if possible.
Sounds like a bug in the custom 10.8.2 build for those Macs, given that it only affects the newest Mac models.