Since installing 15.4, I've noticed Amarok frequently stops.  With 15.3,
it would play for hours without issue.  Sometimes it will play a single
song, then stop.  Other times it will play a few songs before stopping. 
Looking that the title line right now, I don't see a next song listed. 
I do see the previous song, which it stopped after.  I then had to click
on play again.  Sometimes, clicking the play button doesn't do anything
and I have to click on a song to start playing again.

It's Amarok v 2.9.71