Ajax Multiple Callbacks is not working for first callback?
You don't need multiple ajax callbacks, you need multiple ajax commands.

First wrap each form element in a separate div container and then return for each one an ajax command from the same callback:

use Drupal\Core\Ajax\AjaxResponse;
use Drupal\Core\Ajax\ReplaceCommand;

...

  function example_ajax_callback(&amp;$form, FormStateInterface $form_state) {
    $response = new AjaxResponse();
    $response-&gt;addCommand(new ReplaceCommand('#example-wrapper1', $form['field_example1']));
    $response-&gt;addCommand(new ReplaceCommand('#example-wrapper2', $form['field_example2']));
    return $response;
  }