in reply to
Which takes priority site\lib or lib?
On newish perls (I'd guess since perl 5.12, but I could be wrong), site/lib takes precedence over lib, to allow "overwriting"/shadowing/updating of core modules without touching the core package.
And why has it suddenly started installing itself in a different place?
The idea is that package managers (like activestate's ppm, or debian's dpkg) install into lib/, and CPAN installers into site/lib. Since the "Reveal this spoiler" link doesn't work for me (says "No such parent node"), I can't tell whether it worked as expected.