Bug in Smart Playlist sync of blank genre field from iTunes (12.13.5.3) to iPhone (18.3.1)

I am posting this here because the feedback form for submitting bugs has a limit of 800 characters, and this bug cannot be described accurately within that limitation.

Problem: Smart playlists that contain a filter on the genre field are not syncing correctly with the iPhone when the genre of an item is blank.

Example: Song1 has no genre defined in its info. Song2 has the genre 'Rock' in its info. Song3 has the genre 'Blues' in its info. All three songs have the same artist, 'ArtistA.'

A smart playlist, 'Playlist1' is created in iTunes with the following criteria: Artist is 'ArtistA.' All other options are left at their default values.

A smart playlist, 'Playlist2' is created in iTunes with the following criteria: Artist is 'ArtistA.' Genre is not 'Jazz.' All other options are left at their default values.

The expected behavior of both Smart Playlists in iTunes is that both should correctly show all 3 songs, as all 3 songs have artist 'ArtistA' and none of the 3 songs are of the genre 'Jazz.' iTunes correctly does this.

The expected behavior when syncing both Smart Playlists with the iPhone is that both Smart Playlists will be accurately replicated on the device and will contain all 3 songs, just like in iTunes. This does not correctly occur, and instead we see the following:

On the iPhone, 'Playlist1' correctly shows all 3 songs in the music app as expected. 'Playlist2' however only shows Song2 and Song3. The inclusion of the filter "Genre is not 'Jazz'" in the iTunes Smart Playlist incorrectly excludes Song1, which has no defined genre. Only when Song1's info is modified in iTunes to have any data in the genre field (except of course 'Jazz'), will it then correctly be shown in the synced Smart Playlist on the iPhone.