Kubernetes horizontal pod autoscaling initial delay?
This flag actually exists: --horizontal-pod-autoscaler-cpu-initialization-period In addition you need to consider the readiness delay: --horizontal-pod-autoscaler-initial-readiness-delay and the metric loop time, --horizontal-pod-autoscaler-sync-period to calculate the total (max/min/average) delay.
See https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/