Wow, thats a good one. Kind of a long shot but could the 3150’s at the remote site be trying to PXE boot off another server? Do you have a RIS or some other PXE server dumping out images to PC’s on that site? If this is that case try changing the boot order on the terminal with PXE last and see if it helps.
Its just strage that you take a working device and put it there and it fails and I assume it comes back and works again?