Does my environment have anything to do with this?
You check that with perl -V command, because PERL5LIB isn't the only one
Although even that won't dump your cpan|cpanp|cpanm configurations
Under perlbrew, CPAN clients install architecture-specific files in a common tree, i.e.
That doesn't seem like a perlbrew issue :) see INSTALL_BASE
Although you could argue if perlbrew doesn't protect you from yourself ( from your INSTALL_BASE overrides ) what is perlbrew good for?
An alternative to perl brew (not a bash script) is perlall - build, test and do with all perls