I am using Version 3.4.7726 P which I assume is the latest version.
Something funny is going on with MB and the playlist is not working correctly. If you remove a number from the now playing track, it will jump the next queued track and plays the one after. If one puts a track, before the playing track, it will go back and replays the track already played. If the playlist is put on shuffle, it sometimes plays a number, not in the playlist.
I do not know whether I explained the bug correctly. If not I can send screenshots or do an example.