I am doing some editing work for a magazine. The lead editor had issues with adobe camera raw viewing some of my edits. The xmp files are there but for some reason they are not loading. We narrowed it down to just the Nikon D4 files. I just had her download a trial version of LR4 and we are getting the same issue. The xmp's are there in the same folder as the .nef files. Import into Lightroom, and all D4 files do not show my edits.
We are both running Lightroom 4.3, Camera Raw 7.3.