My Network Monitor plasmoid suddenly stopped showing usage for the Ethernet link, but it still does for the Wifi. The System Monitor (ksysguardd) displays rates correctly. At some point, even though the plasmoid was broken I could see the graph in the NetworkManager systray widget. I tried another plasmoid (Netspeed?) and it had the same problem. /proc/net/dev
has the information (I wrote a short script to use it).
Things could be related to a reboot that upgraded the kernel (currently on 4.13.0-37-generic #42~16.04.1-Ubuntu
), but the Ethernet link kept its name.
Running Kubuntu 16.04