@Timed based metrics are not propagated by Spring Cloud GCP

[Alos]

Describe the bug

Adding a @Timed annotation in a Spring Cloud GCP project does not always propagates its metrics back into Google Cloud Metrics or GCPs Trace UI.

Sample

Annotating methods with @Timed("test-cat-event") should publish this metric to GCP's Cloud Metrics.

@Timed("test-cat-event")
  @Scheduled(
      fixedDelayString = "5",
      timeUnit = TimeUnit.MINUTES)
  public void doTheThing() throws InterruptedException {
    log.info("[doTheThing] Doing the thing...");
    Thread.sleep(7000); // Pause execution
    log.info("[doTheThing] Done!");
  }

The metric is exposed correctly on the actuator /metrics endpoint and I can see metrics working when I run the project locally. However, the metrics are not exposed when running inside of GKE.

Minimal project to reproduce:
https://github.com/Alos/spring-cloud-gcp-metrics-issue