Hey there, are you using this balena-pihole project?
If so, it’s the Pi-hole service that is listening on port 80 for the admin dashboard. Can you provide the value you have set for INTERFACE in the balena dashboard? If you’re using wired it should be eth0 which is the default but if you want to use it via wireless only INTERFACE should be set to wlan0.
The reason you can see the differences on the Host OS is the Pi-hole service has to run with network_mode: host so it shares the networking stack with the host and only binds to the provided interface.