Perl List::pairwise on Windows+ActiveState produces unexpected result

Perl List::pairwise on Windows+ActiveState produces unexpected result

I think that this Perl should produce ['c', undef] but on Windows 7,
ActiveState 5.16 it produces: [].
use List::Pairwise qw(grepp mapp);
my %k = (a=>1, b=>2, c=>undef);
say dump([grepp {!$b} %k]);