map inner map doesn't map

gistfile1.txt

my %h;
%h<n1> := { a => 42 }
%h<n2> := { b => 666 }

my @n = <n1 n2>;
my @d = <a b>;

if %h{@n} -> @dh {
    dd @dh;
    @d.map: -> $d {
        dd $d;
        dd @n;
        @n.map: { die $_ }
    }
}