Private playlists not private

[christyrt07]

Hi, so i just made a new private playlist, and ive never had this problem before. I was listening to it, not in private mode, but the playlist itself was private and my friend texted and told me he was able to see it, and he showed me how he could click into it and look at the whole thing. isnt the playlist supposed to be private?? i dont want to use private session because i like people to see what im listening to, but arent they just supposed to see the song information and album when you are listening to a song from a private playlist? super frustrating because it got me in trouble. 

Plan: Premium

Country: United States

Device: Microsoft Surface pro 4 

Operating System: Windows 10