I just tried on a different adapter, the SMC EZ Connect USB model 2202USB/ETH... it fails with the following error: line 53: udhcpc: not found Oh and dog-- I get the same "connection will be ended" popup all the time now, regardless of connection type. It also doesn't matter how much charge is in the device.
/usr/sbin # usbEthDown.sh killall: usbEthUp.sh: no process killed rm: cannot remove '/tmp/.usbEthUp.lock': No such file or directory