Istio 1.11.8 Multi-Cluster Install - Istiod "x509: certificate signed by unknown authority" errors

Hello. I am attempting to install Istio 1.11.8 following the mult-cluster instructions at Istioldie 1.11 / Install Multi-Primary on different networks. After following the install instructions, I am seeing multiple “x509: certificate signed by unknown authority” errors in the logs for the istiod pod:

2023-01-04T17:14:19.891615Z error watch error in cluster cluster1: failed to list *v1.Pod: Get “[redacted]/api/v1/pods?limit=500&resourceVersion=0”: x509: certificate signed by unknown authority
2023-01-04T17:14:21.467072Z error watch error in cluster cluster2: failed to list *v1.Namespace: Get “[redacted]/api/v1/namespaces?limit=500&resourceVersion=0”: x509: certificate signed by unknown authority
2023-01-04T17:14:24.617469Z error watch error in cluster cluster2: failed to list *v1.Endpoints: Get “[redacted]/api/v1/endpoints?limit=500&resourceVersion=0”: x509: certificate signed by unknown authority
2023-01-04T17:14:25.918370Z error klog error retrieving resource lock istio-system/istio-namespace-controller-election: Get “[redacted]/api/v1/namespaces/istio-system/configmaps/istio-namespace-controller-election”: x509: certificate signed by unknown authority
2023-01-04T17:24:03.415477Z error watch error in cluster cluster1: failed to list *v1.Node: Get “https://myrancher.example.com/k8s/clusters/c-sjrb3/api/v1/nodes?limit=500&resourceVersion=0”: x509: certificate signed by unknown authority

https://myrancher.example.com is a Rancher instance and has a Comodo signed certificate installed and does not have any certificate errors when accessed through a browser. Any idea why istiod isn’t trusting the certificate? Thanks.