公众号语音，接收到的Recognition为空？

<xml><ToUserName><![CDATA[gh_32cf2b593873]]></ToUserName>
<FromUserName><![CDATA[owr0u1UsuhDNywUJi441oTLS3HPU]]></FromUserName>
<CreateTime>1617779933</CreateTime>
<MsgType><![CDATA[voice]]></MsgType>
<MediaId><![CDATA[swkjGx-jEqsWb3sRiO5DrOPA4kgeoI7TkoRB46Fi7L0H-F2WeNK68DSe3K7jtdlZ]]></MediaId>
<Format><![CDATA[amr]]></Format>
<MsgId>23161039643607395</MsgId>
<Recognition><![CDATA[]]></Recognition>
</xml>