this always crashes

crash_3.pl

#!/opt/perl-5.28.0/bin/perl

use v5.28;
use warnings;
use FindBin '$RealBin', '$RealScript';
use lib "$RealBin/local/lib/perl5", "$RealBin/lib";

use DateTime::Format::Strptime;
use Storable 'store', 'retrieve';
use Data::Dumper;
use Scalar::Util 'weaken';

my $foo = [
    DateTime::Format::Strptime->new(
        pattern => '%Y-%m-%d %H:%M',
        time_zone => 'UTC',
    ),
    {},
];

$foo->[1]{a}{b} = $foo->[1];
weaken $foo->[1]{a}{b};


print Dumper($foo->[1]);

store $foo, './big_array.dat';
retrieve './big_array.dat';

Output:

$VAR1 = {
          'a' => {
                   'b' => $VAR1
                 }
        };
sv_upgrade from type 7 down to type 1 at /opt/perl-5.28.0/lib/5.28.0/x86_64-linux/Storable.pm line 414, at ./test.pl line 28.