I have downgraded to the V2.264 as suggested, but I still see packets moving in the TX and RX of ‘tethering’. Also in the Luci ‘overview’ MWAN status both tethering and WAN are ‘online’
I have a cradlepoint ibr600 and when connecting the cable to WAN port the 3G goes offline and packets drop to zero, on disconnecting the WAN cable the interface comes back up.
I don’t think the ‘tethering’ interface goes down as I see a steady increase of TX and RX data which will add up over time particularly over an extended period where I want the 4g as backup.