Songs not there

On many artists, a song from my top list is not there, for example for the clash i can not see my number one song, the list jumps straight to 2 so i assume it knows what number 1 is but isnt showing. And for royce da 59, it starts at song no.1 and then skips to 3. If the sing has been deleted from the algorithm or something it may aswell still be there.