cakephp 2.2.1 Model::save doubles all numeric arrays

gistfile1.php

       function testDoubleSave() {
		$to_save = array(
			'Article' => array(
				'title' => 'title',
				'body'  => 'body',
			),
			'Meta' => array(10, 12),
		);
		$result = $this->Article->save($to_save);
		$expected = $to_save;
		$this->assertEquals($expected['Meta'], $result['Meta']);
	}

Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
 Array (
     0 => 10
     1 => 12
+    2 => 10
+    3 => 12
 )