[explicit-module-boundary-types] Warning for Return Types and Argument Types on Nested Functions

[ccaspers]

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have read the FAQ and my problem is not listed.

Repro

Fully working repro can be found here: https://github.com/ccaspers/explicit-module-boundary-types

module.exports = {
    "env": {
        "browser": true,
        "es2021": true
    },
    "extends": [
        "eslint:recommended",
        "plugin:@typescript-eslint/recommended"
    ],
    "parser": "@typescript-eslint/parser",
    "parserOptions": {
        "ecmaVersion": 12,
        "sourceType": "module"
    },
    "plugins": [
        "@typescript-eslint"
    ],
    "rules": {
    }
};

/* works as expected */
interface Transformer {
  apply(input: number): string;
}

const impl: Transformer = {
  apply(input) {
    return input.toString();
  },
};

/* produces unexpected warnings */
interface NestedTransformer {
  nested: {
    apply(input: number): string;
  };
}

const nestedImpl: NestedTransformer = {
  nested: {
    // Missing return type on function.eslint@typescript-eslint/explicit-module-boundary-types
    // Argument 'input' should be typed.eslint@typescript-eslint/explicit-module-boundary-types
    apply(input) {
      return input.toString();
    },
  },
};

export default {
  impl,
  nestedImpl,
};

Expected Result
There are no warnings for the nested apply function.

Actual Result
There are warnings for the nested apply function.

The following warnings were produced, even though the object is fully typed using an interface:

• Missing return type on function.eslint@typescript-eslint/explicit-module-boundary-types
• Argument 'input' should be typed.eslint@typescript-eslint/explicit-module-boundary-types

Additional Info

Versions

package	version
@typescript-eslint/eslint-plugin	4.12.0
@typescript-eslint/parser	4.12.0
TypeScript	4.1.3
ESLint	7.17.0
node	12.19.1

[ccaspers]

Sorry I should have used the search function before posting this. It's a duplicate of #2864