So someone pointed me to this thread and especially:
I ran the Python scripts and it finds all ssdp/upnp/dlna servers running in my network and I found the one that was culprit and matched the PMS logs which was @ port 1990 of my Asus Router running Merlin.
So the culprit was WPS and when I disabled it, the errors went away.
If yours is at other IP:Ports in the system, you’ll have to go that particular device and change/turn off particular service, assuming it’s not going to disrupt your current network & devices.
