Dumb question please help

[Newb2018]

I’m in the US. Using free version. I’m new to Spotify but I am following a few friends. I’m on an iPhone 8. My problem is when I view a friend’s public playlist, the songs content varies every time I look at the playlist. I can look at it and it might have 5 songs, ten minutes later I look at it and 3 of those songs are there and two have been deleted or replaced. 

Why is it constantly removing and adding songs on this playlist?