Description:
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When I try unset() a property on object not instanced this remove a first proporty, please check the script.

Test script:
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$object = new stdClass();
$object->test = '1'; 
$object->test_unset = '2';

var_dump($object);
$object2 = $object;
unset($object2->test_unset);
var_dump($object);