One music track sometimes won't play

One of the music tracks in my game will sometimes not play. That sounds bizarre, because it is.

It worked perfectly before, and I haven't changed anything in the audio since it did. Sometimes the track will play correctly (the existing background music is stopped before this plays), but now most of the time it will not play at all. The debugger informs me that the track progress is 0 out of NaN (Not a Number) seconds. The other music tracks all work as they should.

What's up with this?

I have not idea and I want to know too. It's annoying. Something about the front of the audio file that browser audio system just doesn't like. I have the same problem. If I put the music up as a sound file it works fine.

so bump.

Update: This also occurs with another tune, which will only work correctly if this is the first level you visit in this session... despite the fact that one other tune (title/menu) will always play before it.