Sorry to raise this thread from the dead but I also have experience of this issue.
Where it's been seen is with WAV files that have metadata appended to the end of the sample data - this seems to be incorporated as part of the sound sample data in the wav file loader.
I have submitted a proposed fix for this - see bug 1280 on bugzilla
and the associated pull request on GitHub
I've already used this fix in my own build of joal and it seems to do the trick (at least on the sample files that were showing the issue)