Podio-PHP not reading array from while-loop correctly

I'm using Podio podio-php for my API to save data from a form to Podio and I haven't had any problems other than this small but annoying one. When I use $visit_arr

-array the fields in Podio are empty, but when I use a hand-created array $visit_array_with_manual_values

it works fine. When I print the arrays ( print_r

), they are identical. I don't know much about objects in PHP, but could the array_push

-function make the $visit_arr

-array less valid for this procedure? Or is the problem elsewhere? thank.

// create array
$visit_arr = array();

// loop through visit items from form
$i = 0;
while ( $i < $num_visit_items ) {
    $j = $i + 1;
    if ( isset( $_POST['visit'.$j.''] ) ) {
        array_push($visit_arr, $_POST['visit'.$j.'']);
    }
    $i++;
}

// alternative array (which works)
$visit_array_with_manual_values = array(123,456,789);

// create item in Podio
$fields = new PodioItemFieldCollection(array(
  new PodioTextItemField(array(
    "external_id" => "titel",
    "values" => $firstname
  )),
  new PodioTextItemField(array(
    "external_id" => "lastname",
    "values" => $lastname
  )),
  new PodioAppItemField(array(
    "external_id" => "visit",
    "values" => $visit_arr
  )),
  new PodioTextItemField(array(
    "external_id" => "description",
    "values" => $description
  ))
));