Your code evaluates to:

$test_subscriptions->{"test_case-$j"} = ['news','updates','vols-annc']
+;
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The rest of the code evaluates to constants in void context. Perhaps you meant to assign an anonymous array instead:

$test_subscriptions->{"test_case-$j"} = [
          'fname' => $lname,
          'lname' => $fname,
            'zip' => '02486',
          'email' => $email,
          'lists' => ['news','updates','vols-annc'],
    ];
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Or an anonymous hash:

$test_subscriptions->{"test_case-$j"} = {
          'fname' => $lname,
          'lname' => $fname,
            'zip' => '02486',
          'email' => $email,
          'lists' => ['news','updates','vols-annc'],
    };
[download]