Store an array in memcached and read it back. Using memcached as backend, it's unserialized correctly to an array, Apache Ignite returns a string

JSON-Deserialize.php

<?php
$mc = new Memcached();
$mc->setOption(Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_JSON_ARRAY);
$mc->setOption(Memcached::OPT_COMPRESSION, false);
$mc->setOption(Memcached::OPT_BINARY_PROTOCOL, true);

$mc->addServer('localhost', 11211);

$data = ['hello' => 'test'];
echo gettype($data) . PHP_EOL;

$mc->set('mykey', $data);

$data = $mc->get('mykey');
echo gettype($data) . PHP_EOL;

php-memcached stores the data type in the flags, an uncompressed JSON serialized array amliken thexple should have a 6 as flag. As I'm getting back a string, I assume Apache Ignite stores a 0.

<?php
$mc = new Memcached();
$mc->setOption(Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_JSON_ARRAY);
$mc->setOption(Memcached::OPT_COMPRESSION, false);
$mc->setOption(Memcached::OPT_BINARY_PROTOCOL, true);

$mc->addServer('10.1.17.102', 11211);

$array = ['hello' => 'test'];
$object = new stdClass();
$object->prop = "value";

$data = [
    'integer' => (int) 5,
    'double' => (float) 3.5,
    'string' => "Hallo",
    'array' => $array,
    'object' => $object
];

foreach ($data as $type => $item) {
    $mc->set($type, $item);
    printf('%s :: %s%s', $type, gettype($mc->get($type)), PHP_EOL);
}

Result with memcached:

int :: integer
float :: double
string :: string
array :: array
object :: array

Result with ignite:

integer :: boolean
double :: string
string :: string
array :: string
object :: string

The data is stored correctly, but the flags are ignored completely... It's also strange that it's impossible to store a plain integer...