I swear I had solved this in Backlight 2.
I use virtual copies to create B&W rendition of images sometimes. On republishing my site I am seeing a lot of instances where the B&W version is publishes as the color version (resulting in apparently duplicate images)
Digging through the old forums I find that Publish Setting, File Rernaming can mess with this, but that is off.
If I export the files any other way, I get correct exports.
Anyone have a solution?