I’ve observed the exact same behavior. Spiked CPU in the Balena dashboard (over 80%) when checking the terminal the machine reports less than 10%.
However, very happy I found this forum since I was looking for a solution for getting WiFi stats in node and the link to system information was exactly what I was looking for!
Looks like that also means my recommendation for getting WiFi stats into the dashboard might also use systeminformation library: Recommendation: RSSI stats in dashboard