$redis->multi();
$redis->hget('test1','a'); //cluster nodes 1
$redis->hget('test2','a'); //cluster nodes 1
print_r($redis->exec());

PHP Fatal error: Uncaught RedisClusterException: Error processing EXEC across the cluster in /root/testr.php:20
Stack trace:

0 /root/testr.php(20): RedisCluster->exec()

1 {main}

thrown in /root/testr.php on line 20

$redis->multi();
$redis->hget('test1','a'); //cluster nodes 1
$redis->hget('test3','a'); //cluster nodes 2
print_r($redis->exec());

is ok....