Issue with setDataSource in CakePHP 2.4.8 - cakephp

Question

I wrote a behavior, Cascadable, that merges records across 2 databases. It works sort of like CSS, where the more local style overrides the global. The behavior uses $this->setDataSource() to switch between the databases. This was working up until the 2.4.8 release when this commit was made to the Model.php file.
Here's sort of an extraction from the behavior:
$Model->setDataSource( 'alt' );
$altData = $Model->find($findType, array(
'contain' => false,
'conditions' => array(
$Model->alias.'.id' => $ids
),
'callbacks' => 'before'
));
If the callbacks option is set to false, I get Missing Database Table errors about tables that are only present in the default (parent) datasource.
I'm not sure what I'm doing wrong here, but after 2.4.8 upgrade it always uses the wrong (parent) database instead of the child. I can revert Model.php back to the 2.4.7 version to fix the issue. I realize this is difficult to replicate because it only breaks in my very specific database structure.
MySQL Table Schema example:
Parent Database Table
CREATE TABLE `products` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL DEFAULT '',
`price` float(8,2) DEFAULT NULL,
`active` tinyint(1) NOT NULL DEFAULT '1',
PRIMARY KEY (`id`),
KEY `active` (`active`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 PACK_KEYS=0;
INSERT INTO `parent_db`.`products` (`id`, `name`, `price`, `active`) VALUES (NULL, 'Big Box of Goodies', '99.99', '0');
Child Database Table
CREATE TABLE `products` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`price` float(8,2) DEFAULT NULL,
`active` tinyint(1) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `active` (`active`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 PACK_KEYS=0;
INSERT INTO `child_db`.`products` (`id`, `name`, `price`, `active`) VALUES (NULL, 'Small Box of Surprises', NULL, '1');
Query Results
From Parent DB
array(
(int) 0 => array(
'Product' => array(
'id' => '1149',
'name' => 'Big Box of Goodies',
'price' => '99.99',
'active' => false
)
)
)
From Child DB with working Cascadable behavior (child record is merged into parent record, ignoring null values)
array(
(int) 0 => array(
'Product' => array(
'id' => '1149',
'name' => 'Small Box of Surprises',
'price' => '99.99',
'active' => true
)
)
)
Workaround:
Setting the schemaName manually after using setDataSource fixes the issue for me.
$Model->setDataSource( 'alt' );
App::uses('ConnectionManager', 'Model');
$dataSources = ConnectionManager::enumConnectionObjects();
$Model->schemaName = $dataSources['alt']['database'];