OK. There are actually 3 questions. The original question is implicitly answered: "I don't have a clean build".
The second question would be "Why don't I have a clean build?". That answer seems to be that CPAN caches everything in a perl5 directory that doesn't reflect the build version. Anyways, by deleting ~/perl5, I am able to get the same results you posted on github.
The $10,000,000 third question, what throws a Attempt to free unreferenced scalar error? My problem seems unrelated to this bug. This 2007 post
is probably the most promising to pursue. Since I'm posting anyways, does anyone have additional insights?