Chromecast and wireguard

On my pfSense I run a wireguard server for remote access when I travel. In my house are 7 Chromecasts (don’t judge, I like them).

Normally I can’t see or cast to the Chromecasts when I have wireguard enabled but today I was able to both see and cast to 3/7 Chromecasts from 2,000 miles away on cellular when using the wireguard VPN.

So now I’m curious. Why can I suddenly see 3 of them and why can’t I see the other 4?

All of the Chromecasts are hardwired with Cat5e and powered 24/7 so it’s not like the other 4 we’re off. The firewall rules for wireguard are a basic allow all outbound. Avahi is not enabled for the wireguard interface. And the wireguard config is a full tunnel.

Any ideas why I can’t see the other 4 Chromecasts?

So I tried it out on my laptop and I get no casting options, but I have them on my Cell phone.

An interesting thing I’ve noticed is that they only show up when the cell phone is on Cellular data, when I’m on any sort of Wifi (like Hotel Wifi) the cast option is gone. If I leave Wifi and go to cellular the casting comes back, but still only 3/7.