Comment 12 for bug 1575251

Steps to reproduce:
Deploy lab with several notification agents.
Add transformer-based metric in pipeline.yaml for example cpu_util:
---
    - name: cpu_sink
      transformers:
          - name: "rate_of_change"
            parameters:
                target:
                    name: "cpu_util"
                    unit: "%"
                    type: "gauge"
                    scale: "100.0 / (10**9 * (resource_metadata.cpu_number or 1))"
      publishers:
          - notifier://

Expected result: receive cpu_util metric every polling cycle for each booted vm
Actual result: cpu_util metrics are received but less often than expected.