Version 4.1.2

system/Data/Cache/Memcache.php

@@ -171,10 +171,10 @@ class _Memcache extends \IPS\Data\Cache
 		else
 		{
 			$value = $this->link->get( \IPS\SUITE_UNIQUE_KEY . '_' . $key );
-			
+						
 			if( method_exists( $this->link, 'getResultCode' ) )
 			{
-				if ( $this->link->getResultCode() == \Memcached::RES_NOTFOUND )
+				if ( $this->link->getResultCode() == \Memcached::RES_NOTFOUND or $value === FALSE )
 				{
 					$this->doesNotExist[] = $key;
 					return FALSE;
@@ -232,6 +232,7 @@ class _Memcache extends \IPS\Data\Cache
 	 */
 	public function clearAll()
 	{
+		parent::clearAll();
 		$this->link->flush();
 	}
 }