@johnrellis I still think there is a problem that could be solved here. As you said the camera to os transfer is apparently not recording the milliseconds in the OS but the catalog has the Original Capture Time Stored IF it was changed in LrC, otherwise it is NULL. The algorithm for changing the Capture time to Original for a group of photos should read the saved originalCaptureTime from the Adobe_Images table if it has a Time or skip if it is NULL. Lightroom shows this on a newly imported image from R6mk2 This is what is recorded in the "Adobe_Images" table   Change the date to 2024   it is Changed in LC Change back to Original. LrC is NOT reading the "originalCaptureTime" from the catalog but from somewhere else, probably OS.            
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