P: "Save Metadata to File" overwrites EXIF tag SubSecTimeOriginal

Issue: When I save metadata from Lightroom Classic via "Save Metadata to File", I lose subsecond EXIF metadata that was originally there in the file. This is new behavior, did not happen in previous versions (though I'm not sure exactly when it started).

Lightroom Classic version: 13.5 [ 202408062022-6258095b ]

System version: macOS 13.6.9

To reproduce:

1) Import a photo that has a subsecond creation date—for my test, I used an iPhone photo imported via mobile sync.

2) Check SubSecTimeOriginal from the command line:

$ -> exiftool -G -s -SubSecTimeOriginal /Volumes/Media/Photos/Import/Mobile\ Import/IMG_6067.HEIC 

[EXIF]          SubSecTimeOriginal              : 389

3) In LrC, run the "Save Metdata to File" command

4) Check SubSecTimeOriginal from the command line:

$ -> exiftool -G -s -SubSecTimeOriginal /Volumes/Media/Photos/Import/Mobile\ Import/IMG_6067.HEIC 

Warning: [minor] Bad format (16) for MakerNotes entry 14 - /Volumes/Media/Photos/Import/Mobile Import/IMG_6067.HEIC

(That warning does not seem directly connected to the issue, but may be a sign of something unexpected happening...)