Description:
------------
the array that is to be passed to array_unshift() has strings as its keys. if a key is a number, array_unshift does not keep the type string for this key in the resulting array. in the following example, the top level key [1] should in fact be [181050] (as a string). it is index [1] because the first entry is [0], which in fact is meant to be an integer value. an example how i used unshift to insert the first entry in the already existing array:

array_unshift ($relativeCampaignData_A, array ('id' => 0, 'title' => 'k.A.'));

(usually the [id] entries are strings, the first top array element is an exception.

the resulting array is:

Array
(
    [0] => Array
        (
            [id] => 0
            [title] => k.A.
        )

    [e94a5a] => Array
        (
            [id] => e94a5a
            [title] => example1
        )

    [0f298f] => Array
        (
            [id] => 0f298f
            [title] => example2
        )

    [1] => Array
        (
            [id] => 181050
            [title] => thisKeyIsTheError
        )

    [1cfb8b] => Array
        (
            [id] => 1cfb8b
            [title] => example3
        )

)

before using unshift index [1] was associative index [181050] as a string by using strval.

Reproduce code:
---------------
$array = array('123abc' => array('id' = '123abc', 'title' = 'example2'), '456789' => array('id' = '456789', 'title' = 'errorexample'));

print_r ($array);
echo '<br><br>';

array_unshift ($array, array('id' => 0, 'title' => 'example1'));

print_r ($array);

Expected result:
----------------
$array [0] = array
$array ['123abc'] = array
$array ['456789'] = array

Actual result:
--------------
$array [0] = array
$array ['123abc'] = array
$array [1] = array