ACM displays an "x509: certificate signed by unknown authority" error after updating the API certificate for managed clusters

Issue

• Scaling a managed cluster by adding or removing a worker node does not occur as expected. The new number of nodes is displayed in RHACM, but the scaling action does not take place.
• An "x509: certificate signed by unknown authority" error is shown in the ClusterDeployments and hive-controller Pod logs when adding a worker node.
• After provisioning an OpenShift Container Platform cluster with the multicluster engine operator, reimporting the cluster may fail with an "x509: certificate signed by unknown authority" error.