According to [this PR](https://github.com/elastic/apm/pull/334) the `sanitize_field_names` option needs to be added to [Kibana's configuration options](https://github.com/elastic/kibana/blob/master/x-pack/plugins/apm/common/agent_configuration/setting_definitions/general_settings.ts) for the .NET agent.
According to this PR the
sanitize_field_namesoption needs to be added to Kibana's configuration options for the .NET agent.