Adding a recommended song to a playlist problem

[caravanio]

Go to a playlist and scroll to the recommended songs. Add one of them to the playlist using the contextual menu that shows upon right-clicking on the selected song with the mouse. You can notice that the song does not disappear from the list of recommended songs as it would have if you have added it to the playlist by clicking the "Add" button on the leftmost side of the song. Now click the aforementioned button - the same song is added twice in the same playlist, which should be impossible.