Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue (see description)
• I have read the FAQ and my problem is not listed.

Playground Link

Minimal example

Repro Code

const collator = new Intl.Collator("en")
const sorted = ["foo", "bar"].sort(collator.compare)

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/unbound-method": "error"
  },
};

tsconfig

No response

Expected Result

The rule should not fire an error for this code, as Intl.Collator.prototype.compare is bound to collator according to the ECMAScript spec.

Actual Result

The rule fires for the use of collator.compare:

Avoid referencing unbound methods which may cause unintentional scoping of `this`.
If your function does not access `this`, you can annotate it with `this: void`, or consider using an arrow function instead. 4:36 - 4:52

Additional Info

This is a duplicate of #4383, which was marked 'unable to repro'. However, the playground example linked in the team response actually reproduces the issue.