Cure:

The timing error can be corrected by using the Validator's text editor to change the line with the error from:

<audio src="7.mp3" clip-begin="npt=83.856s" clip-end="npt=91.185s"

to:

<audio src="7.mp3" clip-begin="npt=83.856s" clip-end="npt=89.260s"

Then save the edited file.

Note:The same process can be used for all timing errors.