This has happened twice now on 2 separate occasions. For the most part I love Apple Music, when I first got it set up I saved all the albums I had saved to my Spotify to Apple Music instead. And they were then all there on my iPhone/Mac/iPad/etc. Since then I've added some more music, and mostly this works. But twice I've had a problem where I've saved music on my Mac (several different songs) and the next day it's disappeared. It seems to be a specific 'saving session' where I've added lots of bits, that set of bits are all missing later. Has anyone else experienced this?