Maybe, but I don't see how I could have mixed up system perl modules with perlbrew installed modules:

$ perlbrew install 5.20.0
$ perlbrew use 5.20.0
$ cpan install DB::SQLite App::DBBrowser
$ cpan --version
/home/linuxer/perl5/perlbrew/perls/perl-5.20.0/bin/cpan version 1.61 c
+alling Getopt::Std::getopts (version 1.10 [paranoid]),
running under Perl version 5.20.0.
[download]

...
  Built under linux
  Compiled at Jun  1 2014 19:27:38
  %ENV:
    PERLBREW_BASHRC_VERSION="0.66"
    PERLBREW_HOME="/home/linuxer/.perlbrew"
    PERLBREW_MANPATH="/home/linuxer/perl5/perlbrew/perls/perl-5.20.0/m
+an"
    PERLBREW_PATH="/home/linuxer/perl5/perlbrew/bin:/home/linuxer/perl
+5/perlbrew/perls/perl-5.20.0/bin"
    PERLBREW_PERL="perl-5.20.0"
    PERLBREW_ROOT="/home/linuxer/perl5/perlbrew"
    PERLBREW_VERSION="0.66"
  @INC:
    /home/linuxer/perl5/perlbrew/perls/perl-5.20.0/lib/site_perl/5.20.
+0/x86_64-linux
    /home/linuxer/perl5/perlbrew/perls/perl-5.20.0/lib/site_perl/5.20.
+0
    /home/linuxer/perl5/perlbrew/perls/perl-5.20.0/lib/5.20.0/x86_64-l
+inux
    /home/linuxer/perl5/perlbrew/perls/perl-5.20.0/lib/5.20.0
    .
[download]

Same steps with the fresh installed 5.21.0 resulting in:

...
  Built under linux
  Compiled at Jun  6 2014 00:09:21
  %ENV:
    PERLBREW_BASHRC_VERSION="0.66"
    PERLBREW_HOME="/home/linuxer/.perlbrew"
    PERLBREW_MANPATH="/home/linuxer/perl5/perlbrew/perls/perl-5.21.0/m
+an"
    PERLBREW_PATH="/home/linuxer/perl5/perlbrew/bin:/home/linuxer/perl
+5/perlbrew/perls/perl-5.21.0/bin"
    PERLBREW_PERL="perl-5.21.0"
    PERLBREW_ROOT="/home/linuxer/perl5/perlbrew"
    PERLBREW_VERSION="0.66"
  @INC:
    /home/linuxer/perl5lib
    /home/linuxer/perl5/perlbrew/perls/perl-5.21.0/lib/site_perl/5.21.
+0/x86_64-linux
    /home/linuxer/perl5/perlbrew/perls/perl-5.21.0/lib/site_perl/5.21.
+0
    /home/linuxer/perl5/perlbrew/perls/perl-5.21.0/lib/5.21.0/x86_64-l
+inux
    /home/linuxer/perl5/perlbrew/perls/perl-5.21.0/lib/5.21.0
    .
[download]