I did some checking and have verified that in the latest published version of the script, failing to disable wkEnableAudio when doing the real submit causes the audio to play twice. However, this is often very difficult to notice because if your computer is somewhat fast, the double audio will often start at the exact same time. So instead of sounding like the audio playing twice, it merely sounds like the audio is playing back slightly louder, which is easy to miss. You can verify this by logging the number of calls to wkEnableAudio and verifying in the console that
wkEnableAudio(); wkEnableAudio(); sounds slightly louder than
Edit: Also, if you have lightning mode disabled and submit the answer, wait for the audio to finish, and then continue to the next question, you hear the audio playback two distinct times total. This issue only happens for me if wkEnableAudio isn’t disabled during the real submit.