When using the face recognition to add names to captions automatically, the names are only exported in alphabetical order to the metadata, not LEFT to RIGHT, with the names matching the position that the people are pictured in the photos.
When adding names to photo captions, the names need to be listed in order from left to right and not alphabetically. This should be the default order for adding names to photos using face recognition. It makes no sense to list the people in a photo alphabetically.