Odd behavior with managing playlists and sync

I love the Sync feature. I have two Macs and 4 devices all synced but I have noticed odd things.
Songs missing from master playlists and many duplicated tunes with the same number .

Here is one example I can't explain
I was editing a tune and then looked for it later in the All Songs list and couldn't find but it was there in recently viewed .
Attachment 495Attachment 496

Ok can't delete post so I'll just say I figured it out
The exact duplicates were showing the song in a playlist and the master list interestingly one duplicate was in another key in the playlist.
this often results in duplicates.
Has that been fixed?
Does the program recognize an arrangement that has only changed the key and not duplicate it ?
ie put a number in front of it.

The key in the main list can be different from the playlist.
The main playlist should still show 1 copy if the song is exactly the same.
Could you email us your backup so we can check it?
Thank you Bob!