Drupal 7 - Form Api ajax callback causes Synchronous XMLHttpRequest deprecation - php

Question

I have two forms on my Drupal page, one form is populating its fields when value of the first form is changed (when you choose an item from a select box). It seems to work fine, untill I try to submit the form, which won't do much, since in my browser it says this error:
[Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.
<?php
function my_form($form, &$form_state) {
$form['form_1'] = [
'#type' => 'fieldset',
'#title' => "Select box",
'#collapsible' => FALSE,
'#collapsed' => FALSE,
];
$form['form_1']['id'] = [
'#title' => t('Choose:') ,
'#type' => 'select',
'#options' => [
'1' => 'ONE',
'2' => 'TWO',
'3' => 'THREE'
],
'#required' => '1',
'#ajax' => [
'callback' => 'my_form_state_ajax_callback',
'wrapper' => 'form_edit',
],
];
//--------
$form['form_2'] = [
'#type' => 'fieldset',
'#title' => "This is form",
'#collapsible' => FALSE,
'#collapsed' => FALSE,
'#prefix' => '<div id ="form_edit">',
'#suffix' => '</div>',
];
$form['form_2']['name'] = [
'#type' => 'textfield',
'#title' => 'Name',
'#required' => TRUE,
];
$form['form_2']['button'] = [
'#type' => 'submit',
'#value' => "Create",
'#submit' => ['my_form_submit'],
];
return $form;
}
function my_form_state_ajax_callback($form, &$form_state) {
$values = $form_state['values'];
$id = $values['id'];
if($id > 0) {
$form['form_2']['name']['#value'] = "this works!";
} else {
if(isset($form['form_2']['name']['#value'])) unset($form['form_2']['name']['#value']);
}
return $form['form_2'];
}
How to fix this error? It doesn't really matter what is inside the callback function, it can be empty and the error will still occur.. What am I doing wrong?