If you are having problems with your NGINX ingress controller that are preventing requests from being handled as intended please make sure that the Proxy-buffering should be disabled to process requests without waiting for the initial request to finish, and you can also use the particular annotations to regulate how requests are handled. For more details, see here.

Additionally you can try utilizing ingress controller annotations and server-snippet annotation, or you can override the current Nginx Ingress Controller's ConfigMap.