The "Providing Gateway" status indicator does not always reflect whether the node is configured as a gateway. There are several situations where this is the case (but there may be more):
The node has switch ports, and a switch configuration that creates multiple virtual Ethernet interfaces (a-la eth0.1, eth0.2, etc).
The node is set up to mesh over Ethernet. In static gateway scenarios (and possibly in some DHCP gateway scenarios) it reports that a gateway is not advertised, even when a static route is set up and it does advertise a gateway.
The "Providing Gateway" status indicator does not always reflect whether the node is configured as a gateway. There are several situations where this is the case (but there may be more):