I tried getting screengrabs of the effect but wasn't able to. But I did manage to get a quick snapshot with the client's phone:
|It's kinda like an Ib Melchior movie.|
What I saw was the Get Info window zooming out quite choppily leaving echoed windows on the screen, then the actual Get Info window was shifted down leaving blank white space above it while it shuddered slightly up and down before the Finder gave up and relaunched.
Playing around with this I had the client zip an individual .NEF, upload it to Box.net, then downloaded it on another machine and tried Get Info after unzipping it. Everything was fine.
I'm not sure where the problem lay but it smells of the old losing-the-resource-fork file problem of the days of yore.
The solution was to just zip the files and then upload, then download them.