查询历史消息记录，为什么from_id是undefined

以下是我查到记录中的一条：

{"target_type":"single","msg_type":"text","target_name":"胡治平 设计师","target_id":"0772","from_id":"undefined","from_name":"undefined","from_type":"user","from_platform":"i","msg_body":{"text":"你好"},"create_time":1507555066000,"version":1,"msgid":447163678,"msg_level":1,"msg_ctime":1507555066464}