I've noticed that the CPU usage display on Ubuntu MATE's built in system monitor (mate-system-monitor) does not display cpu usage correctly. The %CPU field appears to always display as all zeros (pictured in the middle). I found that gnome-system-monitor (pictured on the left) does at least appear to provide some information on CPU usage, even if the numbers are lower than expected (even lower than expected from this thread).
Could it be something wrong with the config or launch flags of mate-system-monitor? Any idea how to fix this and get it to display %CPU correctly?