I found my Genesis saw the iPod Shuffle I loaded up with music as being loaded with videos instead when plugged into the USB port so it would only play one song at a time too. Had to use the 3.5mm aux in instead of the USB port because of it.
One of these days I need to see about pulling that Genesis out to see if I can replace it with a standard double din car radio. I had a Pioneer head unit 13 years ago that did everything the Genesis does, with a friendlier interface and less bugs. The only thing the Genesis has that it didn't was three different zones but it was capable of sending different signals (I.e. Radio and DVD) to the 2 zones it did have. It would be nice to let the kids have movie sound on inside while the wife and I have music on outside.
There's no use crying over spilled milk, unless it's on your keyboard.