I think I reproduced it. It's as simple as:

$ perl 4.pl
Segmentation fault (core dumped)
$ cat 4.pl
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
unless (fork()) {
    my $sz = 2048*1024*1024;
    my $sc = "x" x $sz;
    exit(0);
}
wait();
print Dumper { a => 42};
exit();
[download]

(note that $sz should be adjusted to take almost all free memory)
Now I need verify again which versions are affected and report to either FreeBSD team or Perl Porters. I'll update my post.