The strange thing is, if I go in to "sounds" and go to Desktop Notification, or New Mail Notification or Notification and select "ring 10" as the sound and click "test", the first time, I get the proper sound, the second time I get the tone followed by half the sound which is what I get when a mail comes in.
If I go to a different "place" in sounds, change the sound from the default to "ring 10", test it, but don't check "apply", the sound plays OK. I went back to the other three and tested there and the tone played properly several times. I'm completely baffled.