In my case the solution was:

# Sync CA bundle from webhook to CRD conversion webhook 

CA=$(kubectl get mutatingwebhookconfiguration opentelemetry-operator-eks-desenv-mutation \
  -o jsonpath='{.webhooks[0].clientConfig.caBundle}')  kubectl patch crd opentelemetrycollectors.opentelemetry.io --type=json \
  -p "[{\"op\":\"replace\",\"path\":\"/spec/conversion/webhook/clientConfig/caBundle\",\"value\":\"$CA\"}]"

Ref: https://github.com/open-telemetry/opentelemetry-operator/blob/main/docs/crd-changelog.md#opentelemetrycollectoropentelemetryiov1beta1