LR is putting different descriptions of the same lens, used with the same camera, in the metadata of photos taken on the same occasion. For example: The following two images were taken with the same camera and lens.
They were imported at the same time into LR by copying. The only difference in treatment is that the first was an untouched out-of camera jpeg, the second had been flipped using Preview on the Mac. The one that was flipped has a full description of the lens, the one that was untouched has an abbreviated description. When you show the file in the Finder and read the metadata using Preview, the correct full lens description appears. Why is LR displaying the metadata differently for these two files?