Random devices on secure WiFi network

[NickNPSConsulting]

I have a secured WiFi network managed with a UDM Pro. My WiFi network has a secure password, and I’m surrounded by elderly neighbors that no idea what a WiFi network is. I also do not have a “guest” WiFi network. 
 

Over the past 30 days, I’ve found (2) random devices on my WiFi network. The first was an Amcrest camera, and the second is a WiFi cat litter box (Litter Robot 3). 
 

Has anyone run into this before where you have devices on your network that have no business being there? I blocked both devices. I know I should change my WiFi password, but I have ~75 wireless devices so it’s a real chore.

 

The only thing I could think is this is MAC address spoofing, but who would spoof with a cat litter box?
 

last, is it possible to do MAC spoofing from a remote location and have the device show up as a wireless device ? The device was using data so it was definitley connected. 
 

My main concern here is someone is remotely accessing my network and viewing my cameras. 
 

any suggestions / insight appreciated…