Drupal form submit action changing at random times - php

Question

I have created a custom Drupal module/form that when submitted the action takes you to another page and posts data with it. Pretty standard stuff.
Randomly, the form action changes at random (not set) intervals during the day that are not correlating to anything immediately obvious - for example cron runs. It only happens maybe once or twice a day, so if anyone has any idea what might cause this or point me in the right direction.
Anything anyone feels needs adding, let me know.
The is the custom module code:
/**
* Test form declaration
*/
function test_form($form, &$form_state){
$form['#attributes'] = array('id' => "test-form");
$form['search-field'] = array(
'#type' => 'textfield',
'#title' => t('<span class="highlighted">Test</span>'),
'#attributes' => array(
'class' => array('form-control form-text'),
),
);
$form['submit'] = array(
'#type' => 'submit',
'#value' => 'Search',
'#attributes' => array(
'class' => array('btn btn-default text-hide'),
),
);
return $form;
}
/**
* search form submit
*/
function test_form_submit($form, &$form_state){
$searchQuery = $form_state['values']['search-field'];
$query = array();
if($search <> ''){
$query = array(
'field_geofield_distance[distance]' => '100',
'field_geofield_distance[unit]' => '3959',
'field_geofield_distance[origin]' => $search
);
}
drupal_goto('test-page', array('query' => $query));
}

Answer 1

If your form creates data (let's say a node) possibly you have a redirection on rules when creating a node that with specific values redirects to another page.
Look for rules that are activated when content creation occur or when submission occur.
Also you could have some redirection magic in the top of Drupal, like a wrong configuration of an .htacess file. If your form does the same thing always it should behave the same always. And why it's redirecting to page of old site?
Finally, if the new site have code from the old site the check submission, creation and form altering hooks.
Hope that helps.