Good questions, I’ve only tried with one other device so far which worked as expected with the traffic controller rule. I’ll have to test that rule with some other devices this weekend.
Connected via WiFi, no switch, bridge, extender etc. It is a smart home device, and not something I can directly log into and check connectivity, but have to instead observe it from other devices. It’s strange that it’s visible and pingable and wholly useable from the local network with no traffic rule, but immediately unavailable with the rule enabled. There’s no need for the device to have any external connections which is why I’d like to be able to turn it off somehow!
I’ll apply the rule to some other devices to see how they behave and let you know, thanks!