Weird Stereo problem

[Lisalpedersen]

When I am listening to spotify with my phone it occasionally seems to only play in side of the stereo track. For instance when I was listening to a Scott Bradley song and I could here the acoustics but not the lyrics. I was wearing both headphones, and it did the same from my speakers when I turned off my headphones. This only happens with spotify, and it's happened with two of my devices. (Phone and tablet)