DMCIA Complaint - they have the right external IP but the internal IP is not 192.168.* which is all listed as my available connected devices

Hi all,

I've got kids so I'm assuming this may be one of them, but I got a DMCIA complaint of someone downloading The Orville on my network... it's not me, I can't find the file on any of my devices (not yet at least) so unsure if someone just got on my network to do so. And none of my kids are the type who would be interested in this show. They did give me an internal IP address of 100.76.220.158 which is not what I expected of an internal IP address since all of mine have the standard 192.168.* addresses. Any thoughts on how to look up alternate internal IP addresses or track any history? I don't see anything on my Zyxel router (using Metronet for my ISP) to look up logs.

Thanks