Azure EasyAuth file based configuration "loginParameterNames" not working

We are able to setup a custom OIDC provider using file bases configuration (ARM Template) - we used https://docs.microsoft.com/en-us/azure/app-service/configure-authentication-file-based as reference. Our OIDC provider requires additional parameters and looking at the JSON provided in the link states there should be a parameter named "loginParameterNames" under "login" property for the custom OIDC provider. However this property does not seem to be working. Is there another way to pass additional parameters to custom OIDC providers?