I've written a utility to check all files on the 6TB drive attached to the RPi4 (LE11 14/04/2023) and check their modified time, file size etc and if different to the file on my backup drive copy across.
An important point is that no files have been transferred over to the RPi4 HDD after it was attached to the RPi3 AND the utility was run and everything brought into sync.
I just ran the utility and was very surprised that all 7026 .nfo files needed to be transferred and also 179 .mp4 files. Knowing how long this would take over my 100MB LAN I opted to take the HDD from the RPi4 and hook it up to a USB 3 port on my Windows PC. Imagine my surprise when running the utility there were no .mp4 files needing transfer. I'd checked one file whilst it was on the RPi4. ExanDiff reported the live and backup files to be identical. The modified time on the live file was 16:17:28 on the RPi4 version and 15:17:28 on the backup. However, when connected to the Windows PC both showed 15:17:28
Both the live and backup disks are formatted to exFAT because having them as NTFS when I last tried moving to the RPi4 meant I had a lot of corruptions.
Any suggestion as to why the wrong time is being reported on some files?