You changed

->query_form(@args);
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to

->query_form(\@args);
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but both are ok. So that leaves the bad return value. Fixed:

use URI qw( );
sub url_freeze {
   my $url = URI->new(shift, 'http');
   $url->query_form(@_);
   return $url
}

my $url = url_freeze('/cgi-bin/details', %args);
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It won't freeze recursively, of course.