Not cropped in Lightroom
Cropped in Lightroom
Difference image

You see that is pretty bad. You see it is not just an extra halo that gets created, but also a sort of combing effect arises. Again Lightroom did not scale upon output. This was just the result of cropping. You can see these artefacts immediately in the Develop module in Lightroom when you just cropped.
P.S. I am not the first to point out this problem. Many people have done so before me (example link). I hope this will soon get fixed. You need light objects on dark backgrounds to see these effects (or the inverse). You see that even in pretty standard sort of images these problems can show up. If your image is not so sharp to start with this (the crop-induced artefact) will probably not be an issue. This was shot with a very sharp prime lens that outresolves the D300. However the resizing artefacts will show up even for less sharp images.