Wireless interface says "Error: Network device not found" but it's working


I have received a new wi-fi controller (RT3070) for OpenWRT.

It's working fine: It weas detected, got configured OK and I have a visible AP. I've just to get DHCP, DNS & NAT working.

However, the status shows the wi-fi interface as being in an erroneous state: 'Error: Network device is not present.'

Which 'network device' is it not finding, exactly? Is this a driver issue or OpenWRT?

Thanks for any light you can shed on this.