I don't think it has anything to do with recursion. I think it has to do with how you are using your array reference. In the sub, you are copying the array, and modifying only the copy. I created a small example to illustrate what might be going on:

use strict;
use warnings;
use Data::Dumper;

my @levs;
myfunc(\@levs);
print "$#levs\n";
print Dumper(\@levs);

sub myfunc {
    my ($aref) = @_;
    my @levs = @$aref;
    $levs[0] = 'foo';
    print 'in sub ', Dumper(\@levs);
}

__END__
in sub $VAR1 = [
          'foo'
        ];
-1
$VAR1 = [];
[download]

Compare that with:

sub myfunc {
    my ($aref) = @_;
    $aref->[0] = 'foo';
    print 'in sub ', Dumper($aref);
}
[download]