The core-js polyfill implementation of queueMicroTask() always falls back on process.nextTick() in Node, which schedules execution ahead of promise resolve/reject microtasks. This is not the behavior that you get with Node's native queueMicroTask() function.

Consider the following:

Promise.resolve().then(() => {
  console.log("first");
})
queueMicrotask(() => {
  console.log("second");
})

Using the core-js polyfill you get "second/first", but using the Node 11+ native function you get "first/second".

This could be resolved using Promise.resolve().then(...) instead of process.nextTick(...). I realize there would be a performance penalty, but the alternative is running code in an unpredictable order, which can outright break things.