Lightroom :: Won't Identify Even One Duplicate Image

I have recently undertaken to run a serious test of LR 1.2--as I did with previous versions-- to see if it was at the stage of development where it would improve my workflow over my present applications. Most everything is much better than before, but I have discovered a killer bug.

I work in a group of four other photographers. We are constantly mixing and matching images from our various DBs/shots for client presentations, frequently mixing shots already in a DB with some that are recent and not yet DBed In the end, of course, we want one DB that incorporates all our collective images. This arrangement lends itself to imports that often will contain duplicates of given, uniquely identified, images.

I discovered that even with the box checked to not import duplicates, that LR is hopelessly inconsistent in stopping the import of absolutely identical files with absolutely identical names, extensions, metadata, etc.

As a test, I imported a set of 50 images--various formats, etc--all of which were in LR already. I ran the test three times. The first test resulted in LR identifying 3 dups, the second test 17 dups, and the third 13 dups. I also tried this test using images that were in two separate LR catalogues--identical in every respect. LR did not identify even one duplicate image of the fifty in this case.