opentelemetry-js: Using OTLPTraceExporter and OTLPMetricExporter together causes empty data

What version of OpenTelemetry are you using?

   "@opentelemetry/api": "^1.0.4",
    "@opentelemetry/api-metrics": "^0.27.0",
    "@opentelemetry/auto-instrumentations-node": "^0.27.3",
    "@opentelemetry/exporter-metrics-otlp-proto": "^0.27.0",
    "@opentelemetry/exporter-trace-otlp-proto": "^0.27.0",
    "@opentelemetry/instrumentation-express": "^0.27.1",
    "@opentelemetry/instrumentation-http": "^0.27.0",
    "@opentelemetry/sdk-node": "^0.27.0",
    "@opentelemetry/sdk-trace-base": "^1.0.1",
    "@opentelemetry/sdk-trace-node": "^1.0.1",
    "@opentelemetry/semantic-conventions": "^1.0.1"

What version of Node are you using?

v12.22.1

Please provide the code you used to setup the OpenTelemetry SDK

// Config
import { SemanticResourceAttributes } from "@opentelemetry/semantic-conventions";
import { Resource } from '@opentelemetry/resources'
import { v4 as uuidv4 } from 'uuid';

// Metrics
import { ConsoleMetricExporter, MeterProvider } from '@opentelemetry/sdk-metrics-base';
import { OTLPMetricExporter } from "@opentelemetry/exporter-metrics-otlp-proto";

// Traces
import { BasicTracerProvider, BatchSpanProcessor, SimpleSpanProcessor } from "@opentelemetry/sdk-trace-base";
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-proto';
import { getNodeAutoInstrumentations } from '@opentelemetry/auto-instrumentations-node'

const OpenTelemetry = require("@opentelemetry/sdk-node");

// OpenTelemetry Exporter Config
export const exporterConfig = {
  headers: {
    'api-key': process.env.NR_TOKEN,
    'Content-Type': 'application/x-protobuf'
  }
};

export const OTEL_SERVICE_RESOURCE = new Resource({
  [SemanticResourceAttributes.SERVICE_NAME]: 'otel-express-node',
  [SemanticResourceAttributes.SERVICE_VERSION]: '1.0.0',
  [SemanticResourceAttributes.SERVICE_INSTANCE_ID]: uuidv4()
});

// Create our OTLP exporters
const traceExporter = new OTLPTraceExporter(exporterConfig);
const metricExporter = new OTLPMetricExporter(exporterConfig); // <- Adding this line causes Traces to not be ingested correctly

export function registerTraceProvider() {
    const traceProvider = new BasicTracerProvider({
        resource: OTEL_SERVICE_RESOURCE
    })

    traceProvider.addSpanProcessor(new SimpleSpanProcessor(traceExporter));
    traceProvider.register();
    return traceProvider;
}

export async function otelSetupInstrumentation() {

    // 1. Create and register a Trace Provider
    registerTraceProvider();

    // 2. Create an instance of the OpenTelemetry SDK, passing in our exporter and Resource config
    const sdk = new OpenTelemetry.NodeSDK({
        resource: OTEL_SERVICE_RESOURCE,
        traceExporter: traceExporter,
        // metricExporter: metricExporter,
        instrumentations: [getNodeAutoInstrumentations()]
    });

    sdk.start()
}

What did you do?

Tried to send OTLP trace data to NewRelic.

What did you expect to see?

My trace data to be created and ingested correctly.

What did you see instead?

The following error: One or more OTLP payload(s) was dropped because it was empty.

Additional context

If I remove the line const metricExporter = new OTLPMetricExporter(exporterConfig); everything works fine. My traces are ingested correctly and displayed in the UI.

I am also able to send metric data fine, just not when I try and do both at the same time.

I am confused why simply instantiating an instance of the OTLPMetricExporter would cause my traces to not be sent/formatted properly even though I don’t even pass it into the SDK.