Not receiving cloud run startup latency metric

[neillua]

I am scraping Cloud Run Metrics but the only startup_latencies metric is not showing up.

Hypothesis and things I tried:
1 - Created an exporter for just Cloud Run Container (instead of the whole cloud run) - I was able to get other cloud run container metrics except for Startup Latency

2 - Maybe because it's a beta metric - but I tried scraping beta metrics from other data classes (non-cloud run) and they were producing metrics

3 - Maybe it's the exporter - as I was using a GCP Plugin as well on Grafana instead of via Prometheus + Stackdriver Exporter but in the plugin I see the metrics flowing in fine