I tried it without

}
else {
    $_ = $_;
}
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It didn't work. I tried return in its place, but that also doesn't work, so I just used $_;.

#!/usr/bin/perl

use strict;
use warnings;
use Data::Rmap qw(:all);
use Data::Dump qw(dump);
use Storable qw(dclone);

my $initial = ['note', ['shopping', ['item']]];
my $clone = dclone $initial;

my($dump) = rmap_all {
  if( ref and $_->[0] eq 'shopping' ) {
    my @item = map { [ 'item' => '=>' => $_ ] } qw(bread butter beans)
+;
    my $newdata = [ shopping => \@item ];
    $_ = $newdata;
  }
  else {
    $_
  }
}
$clone;
print dump($dump);
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