Can you post some log (remove sensitive data)? Normally, those events without an extension id in the parties array object are either internal call legs or an event of the external call party. For example, when you receive an incoming call notification events, you will see the extension id in those events with the "Inbound" direction. There are some internal legs with the "Outbound" direction which will not have the extension id. Let me know your event processing logic so I can help.

Check this blog for more info about telephony session event notification.

Hi, Phong.

Thanks for the quick answer. So, I'm aware of all those details (and yes, I've read the blog article of yours -- and thank you for having written it!).

You can see all the 5 (five) call events' payloads that I got for this given call: https://gist.github.com/leandro/396b3d229891ee627c32d520defaa5eb

They are in the "sequence" order. By the way, this is a new call I got since I created this question. It's the second that I face so far since my last deploy (there are probably more calls like these that might have happened before my last deploy). By checking the payloads JSON in the gist above, you can notice that none of the events has the `extensionId` inside the `parties` fragment.

That's strange. Can you elaborate how this call is made. Is it between extensions or an Inbound/outbound call between a PSTN number to a RingCentral direct number, etc?