Unknown Devices on Gateway X2 Coordinator

I have a ConnectPort X2 and using Digi 485 Adapters for my end devices. Been using this setup for years with no issue. That is all working fine. At one site, I am getting many Unknown Devices on my network. Obviously someone else is also using Digi devices around this area. My system will work fine and communicate but then all these devices show up on my network and my communication stops to my devices.

I am using a unique PAN ID for my network as well as encryption. Any advice how to restrict these devices from jumping on my network or any other way to make these devices not obstruct my network communication?

Screenshot of unknown devices on X2’s network page:

https://drive.google.com/file/d/1KSxG9_C32nZr6DDX4-6YFvKc3pIVecxO/view?usp=sharing

For encryption, are you using a unique preconfigured ATKY value that is unique to your devices?

Yes, I believe so. We set Enable encryption (EE) to 1, and we set a unique Link encryption (KY), that is the same on all the associated devices.