When running the cleanup script provided from the github page the script does not remove the klusterlet CRD. So when trying to detach a cluster and import it back you receive the following error:

The cluster cannot be imported because its Klusterlet CRD already exists.
Either the cluster was already imported, or it was not detached completely during a previous detach process.
Detach the existing cluster before trying the import again.

2.8.1

Very

1. oc login to a cluster that has the klusterlet CRD
2. run cleanup shell script 
3. execute generated command from RHACM Infrastructure tab

The cluster cannot be imported because its Klusterlet CRD already exists.
Either the cluster was already imported, or it was not detached completely during a previous detach process.
Detach the existing cluster before trying the import again.

Cluster is connected to hub cluster and becomes available/connected

I found an old bug from a previous version with this same issue https://github.com/stolostron/deploy/issues/179

Here is the cleanup script:
#!/bin/bash
###############################################################################
# Copyright (c) 2020 Red Hat, Inc.
###############################################################################if [ -z "${OPERATOR_NAMESPACE}" ]; then
        OPERATOR_NAMESPACE="open-cluster-management-agent-addon"
fiif [ -z "${KLUSTERLET_NAMESPACE}" ]; then
        KLUSTERLET_NAMESPACE="open-cluster-management-agent"
fiKUBECTL=oc# Force delete klusterlet
echo "attempt to delete klusterlet"
${KUBECTL} delete klusterlet klusterlet --timeout=60s
${KUBECTL} delete namespace ${KLUSTERLET_NAMESPACE} --wait=false
echo "force removing klusterlet"
${KUBECTL} patch klusterlet klusterlet --type="json" -p '[{"op": "remove", "path":"/metadata/finalizers"}]'
echo "removing klusterlet crd"
${KUBECTL} delete crd klusterlets.operator.open-cluster-management.io --timeout=30s# Force delete all component CRDs if they still exist
component_crds=(
        applicationmanagers.agent.open-cluster-management.io
        certpolicycontrollers.agent.open-cluster-management.io
        iampolicycontrollers.agent.open-cluster-management.io
        policycontrollers.agent.open-cluster-management.io
        searchcollectors.agent.open-cluster-management.io
        workmanagers.agent.open-cluster-management.io
        appliedmanifestworks.work.open-cluster-management.io
        klusterlets.operator.open-cluster-management.io
)for crd in "${component_crds[@]}"; do
        echo "force delete all CustomResourceDefinition ${crd} resources..."
        for resource in `${KUBECTL} get ${crd} -o name -n ${OPERATOR_NAMESPACE}`; do
                echo "attempt to delete ${crd} resource ${resource}..."
                ${KUBECTL} delete ${resource} -n ${OPERATOR_NAMESPACE} --timeout=30s
                echo "force remove ${crd} resource ${resource}..."
                ${KUBECTL} patch ${resource} -n ${OPERATOR_NAMESPACE} --type="json" -p '[{"op": "remove", "path":"/metadata/finalizers"}]'
        done
        echo "force delete all CustomResourceDefinition ${crd} resources..."
        ${KUBECTL} delete crd ${crd}
done${KUBECTL} delete namespace ${OPERATOR_NAMESPACE}