I catched a bug in the PEAR object destructor emulation and could isolate the problem in this script.
<?php
$GLOBALS['_call_destruct'] = null;
class foo {
    var $a = "orig value";
    
    function foo() {
        $this->register();
    }
    
    function register() {
        $GLOBALS['_call_destruct'] =& $this;
    }
}updated value: new value
in destructor: orig value

function _destruct() {
    $foo =& $GLOBALS['_call_destruct'];
    echo "in destructor: {$foo->a}\n";
}

register_shutdown_function('_destruct');

$foo = new Foo;
$foo->a = "new value";
echo "updated value: {$foo->a}\n";
?>

This outputs:
updated value: new value
in destructor: orig value

Which means that the value of the "a" property is lost. Really the whole object is equal to the object comming from the constructor instead of the modified one. This doesn't ocurr if you register the object in a method out the constructor.

The correct output of this should be:
updated value: new value
in destructor: new value

-- Tomas V.V.Cox