How can there be an extension with no extension id?

Here's the entirety of a call-log from one extension to another that actually omits the extension id from the last leg. Is it omitted because extensionNumber "1" is invalid? (I can't actually find that extension in our account.)

If this is a misdial, shouldn't the result be something other than 'Missed'?

{ "uri" : "https://platform.ringcentral.com/restapi/v1.0/account/723878016/device/210249608016";,

"id" : "210249608016"

}

},

"transport" : "VoIP",

"legType" : "SipToPstnMetered",

"extension" : {

"uri" : "