First, I hope I did it right.^^
So, when you have a list of tracks, you can scroll as far as the list goes. If you wanna view the thumbnail of the last track, it gets cut, because the picture is below the track.
Now, that we have content below the last track, we can scroll further down.
Here comes the problem, that happens next: When you scroll down to view the entire thumbnail, you cursor will leave the track-zone and the thumbnail disappears, which means that the page jumps back to last track. This leads to the result that you cursor is again on the track-zone to show the thumbnail and the page jumps back, where you tried to view the picture and so on. So, what we see is, that the content of the page always jumps up and down.
I hope it is detailed enough. It is very easy to reproduce this behaviour.
Best, OregoX