I've several GCE instances located two zone: `asia-southeast1-b` and `us-east4-c`. All instances have already install stackdriver agent. In metrics explorer, I can't find `asia-southeast1-b` in `CPU load` metric:

[![enter image description here](https://i.stack.imgur.com/olqAV.png)](https://i.stack.imgur.com/olqAV.png)

But `CPU Usage` is OK:

[![enter image description here](https://i.stack.imgur.com/WrgeL.png)](https://i.stack.imgur.com/WrgeL.png)

What's wrong with this?