KCM is not aware of the AWS Region ap-southeast-3

When installing a HyperShift cluster into ap-southeast-3 (currently only availble in the production environment), the install will never succeed due to the hosted KCM pods stuck in CrashLoopBackoff

4.12.18

100%

1. Install a HyperShift Cluster in ap-southeast-3 on AWS

kube-controller-manager-54fc4fff7d-2t55x                 1/2     CrashLoopBackOff   7 (2m49s ago)   16m
kube-controller-manager-54fc4fff7d-dxldc                 1/2     CrashLoopBackOff   7 (93s ago)     16m
kube-controller-manager-54fc4fff7d-ww4kv                 1/2     CrashLoopBackOff   7 (21s ago)     15m

With selected "important" logs:
I0606 15:16:25.711483       1 event.go:294] "Event occurred" object="kube-system/kube-controller-manager" fieldPath="" kind="ConfigMap" apiVersion="v1" type="Normal" reason="LeaderElection" message="kube-controller-manager-54fc4fff7d-ww4kv_6dbab916-b4bf-447f-bbb2-5037864e7f78 became leader"
I0606 15:16:25.711498       1 event.go:294] "Event occurred" object="kube-system/kube-controller-manager" fieldPath="" kind="Lease" apiVersion="coordination.k8s.io/v1" type="Normal" reason="LeaderElection" message="kube-controller-manager-54fc4fff7d-ww4kv_6dbab916-b4bf-447f-bbb2-5037864e7f78 became leader"
W0606 15:16:25.741417       1 plugins.go:132] WARNING: aws built-in cloud provider is now deprecated. The AWS provider is deprecated and will be removed in a future release. Please use https://github.com/kubernetes/cloud-provider-aws
I0606 15:16:25.741763       1 aws.go:1279] Building AWS cloudprovider
F0606 15:16:25.742096       1 controllermanager.go:245] error building controller context: cloud provider could not be initialized: could not init cloud provider "aws": not a valid AWS zone (unknown region): ap-southeast-3a

The KCM pods are Running