Internal damage to the Windows performance counter may cause the CPU monitoring value for your ECS Windows instances in the CloudMonitor to display as zero or a negative value even though actual CPU usage is a positive value and not at zero. This problem will only affect your Windows instances.
You can run the command, typeperf \Processor(_Total)\% Processor Time, to check whether the counter works properly. If the result is Error: no valid counter, then the counter has failed. You can run the command lodctr /r to fix the counter.