Unknown device in my network

[DemoXC]

Hello there.

I recently scanned my network with Avast Premium Security from my PC (cable-connected). I found out that there's some suspicious device that I don't know. It has no ipv4, after each scan MAC and IP addresses change, also my router and other programs don't see this device at all. When I scan this network from laptop (connected via Wi-Fi) it still show that this device is unknown, but the name and vendor are "Maxlinear, Inc", first 6 chars of MAC refer to Intel. I use Mullvad VPN, but it was disabled.
Is it a threat or nothing to worry about?

[Pondus]

https://www.maxlinear.com/

Turn off all your devices and scan, is it gone?
Then turn on one by one and scan until you see it

[DemoXC]

If I turn off Wi-Fi or LAN-connection I can't scan network on the same device. But if I turn internet connection on another device, this unknown device still in my network.