Blueprint structure can't be correctly saved (serialized)

Hi:
Thanks for the very detailed answer, I really appreciate it. But please note one very important point, I am using my custom FArchive to do the serialization, which is different with the default one used by UGameplayStatics’s functions. My custom FArchive has set Ar.IsSaveGame to true, which leads to another way of the execution, so in that way the BP struct can’t be saved properly.