This is beginning to drive me up a wall. I've got 20 or so galleries of photos I publish on Smugmug with the LR publish plugin. Sometime around the last LR CC update, photos in my published collections began to randomly mark themselves as modified to republish. Photos I haven't touched in years, in galleries I haven't recently changed, all of a sudden appear under 'Modified Photos to Re-Publish.' If I even scroll through a collection, dozens of the images begin to jump up to 'Modified Photos'.
I can select the photos and send them back to 'Published' with 'Mark as Up-to-Date,' but then more immediately jump up to Modified. It's becoming impossible for me to manage my collections, as I can't keep track of which photos I've published. Also, a smart gallery of recently edited photos now wants to upload 900 images, almost all of them not actually recently edited. Since it's a smart gallery, I can't remove them.
What is causing Lightroom to mark all of these images as modified? Any ideas?
There have been a few other reports about this. Please add details about your issue to this bug report in the official Adobe feedback forum: Lightroom: Photos spuriously marked as "edited" | Photoshop Family Customer Community (don't just link to this post -- Adobe is much less likely to read it). Until more people report this problem, it's unlikely Adobe will pay much attention. Be sure to do Help > System Info and report the exact version of LR and version of Mac/Windows you're running -- because of the flaky Adobe CC app, people aren't always running "the latest". Also, please report whether you have Catalog Settings > Metadata > Automatically Write Changes Into XMP checked.