Bug: Playlist changes after ad plays

[EmEmEff]

I've noticed that if I browse the top lists, and start playing "New Music Tuesday" for example, the playlist will play, but after 30 min or so whenever the first ad break comes up, after the ads are done playing (often a collection of Spotify ads), the playlist will change to whatever is on the new "Start" menu which happens to be "Beats to think to" for example.

I can't think if anything I may have done that would cause this. It seems like a bug to me.

I'm using verion Spotify 2.5.0.1664 (free version) on iOS 8.1.3 on an iPhone 4S. (cellular data disabled; wi-fi only).