Ashley I am also running into the same issue when using "audioOnEnded" on Safari which currently break our games in both Yosemite and Maverikcks .
As our users would not be able to upgrade to the new OS, can you recommend or suggest a work around to this bug, or if possible a new method of triggering a sound after another sequentially without having to rely on "audioOnEnded" or timers. This will be very appreciated by the community as it seems to affect a large number of players still on these mac OS's.