"This is caused by either a bug in Node.js or incorrect usage of Node.js internals. Please open an issue with this stack trace..."

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• Version: v14.12.0
• Platform: Linux jillian 5.8.10-arch1-1 #1 SMP PREEMPT Thu, 17 Sep 2020 18:01:06 +0000 x86_64 GNU/Linux

What steps will reproduce the bug?

This occurred while sitting on 2000 concurrent https requests (using a custom agent) across 4 worker threads. ~100 of the requests hit a 2-minute timeout shortly before this happened. In short, this may be difficult to reproduce.

How often does it reproduce? Is there a required condition?

So far, it's only happened once.

Edit: I can reproduce this. 2000 concurrent requests does it, 400 does not.

What is the expected behavior?

No error messages.

What do you see instead?

In text form:

events.js:291
      throw er; // Unhandled 'error' event
      ^
Error [ERR_INTERNAL_ASSERTION]: This is caused by either a bug in Node.js or incorrect usage of Node.js internals.
Please open an issue with this stack trace at https://github.com/nodejs/node/issues

    at assert (internal/assert.js:14:11)
    at JSStreamSocket.doWrite (internal/js_stream_socket.js:165:5)
    at JSStream.onwrite (internal/js_stream_socket.js:33:57)
    at Socket.ondata (internal/js_stream_socket.js:77:22)
    at Socket.emit (events.js:314:20)
    at addChunk (_stream_readable.js:307:12)
    at readableAddChunk (_stream_readable.js:282:9)
    at Socket.Readable.push (_stream_readable.js:221:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:188:23)
Emitted 'error' event on process instance at:
    at emitUnhandledRejectionOrErr (internal/event_target.js:542:11)
    at MessagePort.[nodejs.internal.kHybridDispatch] (internal/event_target.js:357:9)
    at MessagePort.exports.emitMessage (internal/per_context/messageport.js:18:26) {
  code: 'ERR_INTERNAL_ASSERTION'
}

In picture form: