This bug has been driving me absolutely insane. Every time I publish a picture in Lightroom via the SmugMug plugin, each and every new photo that gets published then reappears under 'Modified Photos to Re-Publish'! Other photos in the album also randomly get marked for republish it seems, every time there is something new to publish (I largely use smart galleries, so new photos get added all the time).
I got very confused in the beginning and since I had just reorganised all my keywords, I thought that was what was causing the random republish. After a week of constantly clicking on 'publish' for ALL my albums, now I've completely lost track which photos really need to be re-published because of the keyword changes, and which have just appeared suddenly AGAIN (because even after I re-publish an entire album, it ALL appears in 'Modified Photos to Re-Publish' AGAIN!!!) I have found that I can 'mark a photo as up-to-date', but is there any way I can 'scan' or sync my LR with SmugMug so that both sync seamlessly? Without clicking 'publish' on every single album? I have thousands of pictures!