https://bugzilla.redhat.com/show_bug.cgi?id=1085704
--- Comment #1 from Miro HronĨok mhroncok@redhat.com --- Honestly, I have no idea how to fix this. I will report this upstream, but chances are, the bug is in some of the used Perl module.
Looking at [1] it is clear the test was introduced there and that's the reason why it was OK on RC2.
[1] https://github.com/alexrj/Slic3r/compare/1.0.0RC2...1.0.0RC3