I've been using LR and SM plugin daily for several years, very comfortable with my workflow and rarely have issues that I can't find the solution for in the forums or through searches.
Recently (Oct/Nov 2017), whenever I browse galleries in LR that are in my Smugmug collections (library grid viewing mode), images instantly begin to pop from the 'published' section to 'modified photos to re-publish'. They do this slowly, without any changes being made by me. No changes to the image are showing up in the develop module history section either.
Nothing is being changed in those photos, they don't start to move to the modified section until I am looking at them in the library grid. I thought this might be related to the ACR / Camera Calibration being updated from version 3 2012 to version 4 current, but the photos that are being marked as 'modified' still show version 3 2012 as their calibration.
Any idea what is causing this, how I can stop it? As you can imagine it's throwing quite a wrench into my workflow.
Lightroom Classic CC 7.0 Camera Raw 10.0
Smugmug Lightroom Plug-in 220.127.116.11
Mac Pro (late 2013)
3.7ghz 24GB ram
OS X El Capitan
Are you using Cmd+S to save metadata to file/XMP?
No. I import with a metadata preset and then add descriptive captions, but don't usually make any changes to metadata fields after that.
If there have been no metadata changes you may have hit a longstanding bug which has been driving some of us nuts and which appears to have no fix.
My work around, where I’m certain nothing has changed, is to select all thumbnails in the modified section and right-click (control-click) and choose “Mark as up to Date”
It’s a bit of a pain and sometimes takes two or three instances but everything then gets moved back to the published section.
You can also choose modification options in the SmugMug plugin manager. Metadata usually includes: captions, titles, keywords, geolocation and comments.
I suspect this might be another instance of the bug reported here: Lightroom: Photos incorrectly considered as "changed" by republishing and smart collections | Photos... . When a new version of LR adds a new develop setting (in this case, the Range Mask), it doesn't add that setting to all existing photos immediately. Rather, it does it on the fly as you give LR commands that access the photos (e.g. generate a 1:1 preview). It's this adding of the new develop settings that fools the publishing mechanism into thinking the photo has changed.
Unfortunately, I can't reproduce this using the steps in the bug report, so I can't confirm my hypothesis.
I run into the same bug with my smugmug publish folders. Really annoying. My guess is that John is exactly right.
Yeah, this bug has been around for a while in one form or another. Apparently, when new features are introduced in new versions of Lightroom, photos published in older versions of Lightroom are marked to republish. The new-version metadata upgrade causes old-version published photos to get flagged as modified and jump up to 'republish' for no apparent reason. The Lightroom team knows about this problem, but so far hasn't fixed it.
The best workaround I've found is to edit all published images in the new Lightroom version. Make a small edit to all published images and then reverse it. That updates the metadata to the newest LR version, which prevents the bug from being triggered. Then just mark all published images as up to date, and all will be well with published collections again. Until Lightroom adds another feature. It's quite maddening when published collections start randomly going haywire. Adobe really needs to address this issue.
Lots of past discussion here, along with a response from Adobe congratulating frustrated users for diagnosing the bug and coming up with temporary workarounds. But then electing not to fix it:
OR simply select the "changed" photos and then choose "Mark as published" in LR...done
That doesn't work if your galleries are in folders. You have to go in to each folder, wait for it to mark all the images as modified, then right click and mark as up to date. This is inconvenient to say the least.