@shaunK Yes mate. I have a Mac Mini hooked up to an 8TB external Thunderbolt disk. The disk has started randomly dropping out (Improper dismounting error messages) so I'm worried I'm going to lose all my tunes.
I can't say I've noticed either of the things you've mentioned, but I will have another look tonight. Ideally I want to copy the entire /iTunes/music folder and subfolder structure up to icloud.
Out of interest, are you running OSX High Sierra? You noticed many bugs? Since putting that on, I can't disable the IR receiver anymore, so when I operate the AppleTV with the remote, it keeps loading iTunes on the Mac and playing songs. Annoying!!
Cheers Rich, I might go with that if I can't get this to work......or my BT account has a bunch of storage too.