With questions/posts going back 8 years, this seems like such a simple thing with large capacity to annoy!
Random should mean random. Not random only after the first song.
I *think* I've come up with a simple solution, but I don't know how you'd implement it without expecting the user to do it manually.
Could there be an option to automagically insert a 1 second "blank" mp3 file to the top of the playlist? That's what I've done manually and it certainly works. Now when I play the playlist, it still plays the first song everytime, but I don't care because it is only 1 second long. Everything is randomized after that.
Meanwhile, I have no problem doing it manually myself.