Dang, even a simple foreach produces the same unblessed reference error:

my $max_bigint = $result[1];
foreach (@result) {
    if ($_ > $max_bigint) {
        $max_bigint = $_;
    }
}
say $max_bigint;
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Can't call method "can" on unblessed reference at 
C:/Languages/Perl/perl/lib/Math/BigInt.pm line 2693.
at trial_division.pl line 12.

main::__ANON__('Can\'t call method "can" on unblessed 
reference at C:/Languag...') called at C:/Languages
/Perl/perl/lib/Math/BigInt.pm line 2693

Math::BigInt::objectify(2, 'Math::BigInt', 
'ARRAY(0x3faefc)', 'Math::BigInt=HASH(0x3fb1bc)') called at 
C:/Languages/Perl/perl/lib/Math/BigInt.pm line 1050

Math::BigInt::bcmp('Math::BigInt', 'ARRAY(0x3faefc)', 
'Math::BigInt=HASH(0x3fb1bc)') called at C:/Languages
/Perl/perl/lib/Math/BigInt.pm line 65
        
Math::BigInt::__ANON__('Math::BigInt=HASH(0x3fb1bc)', 
'ARRAY(0x3faefc)', 1) called at trial_division.pl line 55
[download]

It the exact same stack trace as when I tried to use List::Util::max().