Helm chart deployment fails

Please help us with deployment of the service in TRAIN k8s cluster. I tried to deploy it via existing deployment/helm chart but got error:

Error: YAML parse error on signer/templates/istio/autorization-rules.yaml: error converting YAML to JSON: yaml: invalid map key: map[interface {}]interface {}{"include \"my_chart.fullname\" .":interface {}(nil)} 

another question: it looks like the service deployment requires components like istio. Is it strictly required? Is it possible to deploy and use signer in some test env without additional components?