I created a rule to prevent WAN from accessing my camera, but the rule seem to be ignored. I can still access it while on my 5G cell connection. I'm not connected to VPN server. Is this a bug?
I would assume that the camera talks to WAN, not the other way around.
Since the firewall is stateful, it won't block the connection then. You would need to block WAN access from the camera as well.
If you don't forward a camera port from your public IP to your private IP, no one from outside can access your camera.
If you think this isn't the case because you're using an app to connect to the camera (it may have cloud services), then you should block the camera's internet access. Therefore, your rule is backwards: LAN source, WAN destination.
I figured out why the rules are not working. It's because I have my Torguard VPN client active. To find a workaround, I did the following:
Add the camera or devices you don't want to use VPN
Using these settings no traffic could access the cameras. I can still access the cameras when I'm on the same network and when I'm connected to the router's VPN server anywhere in the world.