Unfortunately I cannot reproduce the issue with the above code/data.
Could you provide more info to reproduce the issue ? Thanks.

Thanks for trying. I'll see what I can do.

Ah. My belief was mistaken. I think I have led you up the garden path, for which I apologize.

The request object is indeed created in the code

my $spf_request_object = eval { Mail::SPF::Request->new(...) };

using the data given in my OP, but the exception actually occurs on this call

my $spf_result_object = $spf_server_object->process($spf_request_object);

The request object to be processed was created by the preceding call to Mail::SPF::Request->new(...).

I'm very sorry if I've wasted your time. :(

Will you need to know more about the creation of $spf_server_object to investigate this?

The sample I am using to test is:

use Mail::SPF;

my $s = eval { Mail::SPF::Server->new(); };
my $r = Mail::SPF::Request->new(
versions => [1],
scope => 'mfrom',
identity => '[email protected]',
ip_address => '66.163.191.21',
helo_identity => 'sonic328-46.consmr.mail.ne1.yahoo.com',
);
print $s->process($r);

Maybe the initialization is different.

I have taken an axe to my code to create from it a test harness to try to reproduce the exceptions.

This is on the same machine, so it uses exactly the same perl and the same modules.

So far, I too have failed to reproduce the issue.

I will continue to investigate but for now the ball is firmly back in my court.

Thank you for your patience.

Oh, rats. I clean forgot to hook the handler...

$ cat test_spf_object.pl
#!/usr/bin/perl
use Net::DNS;
use Mail::SPF;
sub xm_DIE_handler { print "$_[0]\n"; }
$SIG{DIE} = &xm_DIE_handler;
my $spf_server_object = Mail::SPF::Server->new();
my $spf_request_object = Mail::SPF::Request->new( versions => [1], scope => 'mfrom', identity => '[email protected]', ip_address => '66.163.191.21' );
my $spf_result_object = $spf_server_object->process($spf_request_object);

$ ./test_spf_object.pl
neutral-by-default (Default neutral result due to no mechanism matches)
NetAddr::IP IPv4-mapped IPv6 address expected (EInvalidOptionValue) at /usr/local/share/perl/5.32.1/Mail/SPF/Util.pm line 128.

pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
$

Thank you, github, for bowdlerizing my code again.

Let's try with triple backticks:

$ cat test_spf_object.pl
#!/usr/bin/perl
use Net::DNS;
use Mail::SPF;
sub xm_DIE_handler { print "$_[0]\n"; }
$SIG{__DIE__} = \&xm_DIE_handler;
my $spf_server_object = Mail::SPF::Server->new();
my $spf_request_object = Mail::SPF::Request->new( versions => [1], scope => 'mfrom', identity => '[email protected]', ip_address => '66.163.191.21' );
my $spf_result_object = $spf_server_object->process($spf_request_object);

$ ./test_spf_object.pl
neutral-by-default (Default neutral result due to no mechanism matches)
NetAddr::IP IPv4-mapped IPv6 address expected (EInvalidOptionValue) at /usr/local/share/perl/5.32.1/Mail/SPF/Util.pm line 128.

pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
pass (Mechanism 'ptr:yahoo.com' matched)
$