The spec.storage.tls.caName field in the TempoStack CRD directly reflects the ConfigMap name in the Pod, so ConfigMaps with names containing dots cannot be specified. In TempoOperator versions prior to 0.7.0 the name was fixed as "storage-ca", so this issue did not occur.
https://github.com/grafana/tempo-operator/blob/v0.7.0/internal/manifests/manifestutils/storage.go#L14

Tempo Operator 0.10.0-6

Create TempoStack CRD with a storage which is signed by a custom CA

1. Create TempoStack CRD by configuring a storage CA - e.g. openshift-service-ca.crt

~~~
  storage:
    secret:
      name: tempo-odf
      type: s3
    tls:
      caName: openshift-service-ca.crt
      enabled: true
~~~

2. pods will fail with below error

~~~
failed to create objects for tracing-tempo: Deployment.apps "tempo-tracing-tempo-query-frontend" is invalid: [spec.template.spec.volumes[3].name: Invalid value: "service-ca.crt": must not contain dots, spec.template.spec.containers[0].volumeMounts[2].name: Not found: "service-ca.crt"]Deployment.apps "tempo-tracing-tempo-querier" is invalid: [spec.template.spec.volumes[2].name: Invalid value: "service-ca.crt": must not contain dots, spec.template.spec.containers[0].volumeMounts[2].name: Not found: "service-ca.crt"]Deployment.apps "tempo-tracing-tempo-compactor" is invalid: [spec.template.spec.volumes[2].name: Invalid value: "service-ca.crt": must not contain dots, spec.template.spec.containers[0].volumeMounts[2].name: Not found: "service-ca.crt"]
~~~