Disable scaledown of Ingressgateway pods autoscaler in istio-operator

Hi,
I am struggling to find out the right configurations for enabling auto scale of istio-ingressgateway in IstioOperator.
I need to disable the scaledown using hpa policy. Can someone please help me with the configuration?

This is what I am using, which doesn’t seem to be working:
Autoscale is enabled as I can see the hpa but the policy is not added.
values:
gateways:
istio-ingressgateway:
autoscaleEnabled: true
autoscaleMax: 15
autoscaleMin: 1
autoscaleBehavior:
scaleDown:
selectPolicy: Disabled