How can I delete "orphaned" files from iPod Nano that don't appear in iTunes?

- iPod Nano (Latest generation)
- iTunes 12.0.1 (Latest version)
- OSX 10.9.5

I'm having issues with my latest generation iPod Nano and iTunes that I don't think were there before I updated iTunes to 12.0.1...

1) When my iPod Nano is connected to my computer and opened in iTunes most of the iPods playlists are empty or almost empty. Yet, when I disconnect the Nano from my computer/iTunes, I can see all the files that should be there. Does anyone know why this is happening?

2) I have 14 "orphaned" podcast files that appear in my iPod Nano Podcasts list when the Nano is NOT connected to my computer/iTunes that do not appear when the Nano is connected to my computer/iTunes. Can someone tell me how I can delete those files?

3) Is this something that can be fixed if I update my Macbook Pro to Yosemite?

Thanks

Anyone?