Lightroom is changing the date modified on some of my old image files when I import new files.
I use Bridge and ACR to process all images, rarely Lightroom. When I'm finished processing with Bridge/ACR I use Bridge to move raw, tifs, and jpegs to various folders in my master image library. Occasionally, I'll launch Lightroom and tell it to import all new stuff it can find anywhere in the entire image library. That takes a while to scan 47K + images in a folder structure with many sub-folders, but the results look OK. Only files I recognize as new get imported. I then use Lightroom only to search and filter the library because it is much better at that task then Bridge. Example: find all high ISO images from 2 cameras to test a new noise reduction tool.
I use the SyncBack utility to backup the image library to an external HDD. SyncBack first compares the master to the old backup and shows a list of new files that will be copied to the backup. Recently, I noticed a lot of old files on this backup list. Files I am sure have not been touched in a long time, but their date modified is recent. By "recently" I mean in the last 3 months since I built an all new Windows 11 machine, installing all software from scratch. I let Lightroom build a new catalog from scratch.
I've now run tests to confirm that it is Lightroom that is changing the date modified on old files. It appears random and hits all file types. Sometimes it is less than 10, sometimes over 100. To test, I run SyncBack to update the backup. Then I run it again to confirm there is nothing new to backup. Then I run Lightroom and import anything not already in the catalog. Then I run SyncBack again, and voila!, it finds old files to backup because their date modified has changed to the time of the Lightroom import.
So, anybody have a clue why this is happening. Can anybody else confirm? It's a PITA because the backup utility takes longer to run. And I can no longer search for everything I've done in the past 3 months because the search it littered with tons of false positives.