Hey,
/var/run/dbus/system_bus_socket is the default socket address dbus client uses, and it should be overridden with the environment variable DBUS_SYSTEM_BUS_ADDRESS with a different address - the socket mounted from the host system using the io.balena.features.dbus label on the iimage.
From the log message you presented, it looks like DBUS_SYSTEM_BUS_ADDRESS variable is not set for the container.
Could you please check if you have its value defined as an application or device environment variable.
https://www.balena.io/docs/learn/manage/serv-vars/