Cloning nodes between multisite instances with separate databases
I wouldn't use the approach you used. Here is my recommendation. 

First, define your database connection to each multisite on the default setting.php with different name, check the example below: 

#Default site 

$databases['default']['default'] = array (
  'database' =&gt; 'dbname',
  'username' =&gt; 'uname',
  'password' =&gt; 'password',
  'prefix' =&gt; '',
  'host' =&gt; 'host',
  'port' =&gt; '3306',
  'namespace' =&gt; 'Drupal\\Core\\Database\\Driver\\mysql',
  'driver' =&gt; 'mysql',
);

#Site 1
$databases['site1']['default'] = array (
  'database' =&gt; 'dbname',
  'username' =&gt; 'uname',
  'password' =&gt; 'password',
  'prefix' =&gt; '',
  'host' =&gt; 'host',
  'port' =&gt; '3306',
  'namespace' =&gt; 'Drupal\\Core\\Database\\Driver\\mysql',
  'driver' =&gt; 'mysql',
);

#Site 2
$databases['site2']['default'] = array (
  'database' =&gt; 'dbname',
  'username' =&gt; 'uname',
  'password' =&gt; 'password',
  'prefix' =&gt; '',
  'host' =&gt; 'host',
  'port' =&gt; '3306',
  'namespace' =&gt; 'Drupal\\Core\\Database\\Driver\\mysql',
  'driver' =&gt; 'mysql',
);




Now, on hook_node_insert you can save the node object to multiple databases by changing the database each time, refer the code below as an example:

// Switch to site 1 database 
\Drupal\Core\Database\Database::setActiveConnection('site1');
//$node will have all fields you need 
$site1Node = Node::create([
    'type'        =&gt; $node-&gt;getType();,
    'title'       =&gt; $node-&gt;getTitle();,
    'body_text'   =&gt; $node-&gt;get('body')-&gt;value,
]);
$site1Node-&gt;save();
// Switch to site 2 database 
\Drupal\Core\Database\Database::setActiveConnection('site2');

$site2Node = Node::create([
    'type'        =&gt; $node-&gt;getType();,
    'title'       =&gt; $node-&gt;getTitle();,
    'body_text'   =&gt; $node-&gt;get('body')-&gt;value,
]);
$site2Node-&gt;save();

// finnally make sure to swich back to default datyabase 
\Drupal\Core\Database\Database::setActiveConnection();