That is exactly what I mentioned in the previous post. There may be some dynamic data which requires correlation and that's why it is not updating the backend.
Java Over htttp protocol, out of the box can deserealize only specific contents types (standard Java serialization, gZip). The binary data used by your application doesn't fall under the mentioned content types and it cannot handle.
If you know the serializattion type used by your AUT, you can implement the logic on your own by consulting the AUT developers.