Readiness check issue with the eck-stack charts

I deployed eck-stack charts v0.16.0 but found the pod readiness check never succeed.

I see it uses this command bash -c /mnt/elastic-internal/scripts/readiness-port-script.sh
I tried inside the pod got Elasticsearch is not ready yet. Check the server logs.

However I did not find any error in the log. It seems the service is healthy as I can hit the endpoints. Any idea?