As attachment i have an object which produces following Warning:
(msgpack_unserialize_map_item) Invalid references value: 29696
This Behaviour was tested and reproduced under following conditions:
php_only was set to true,
php7.4 with msgpack-master
php7.4 with msgpack 2.0.3
php7.4 with msgpack 2.1.0
php 7.2 with msgpack 2.0.2

simple script to reproduce:

<?php
$data=unserialize(file_get_contents('php_serialized.txt));
// echo is empty and msgpack issues a warning 
// there should be no warning and echo should print 1
echo $data == msgpack_unpack(msgpack_pack($data)));

Any help on how to debug this would be appreciated
php_serialized.txt