VSCode not showing @returns on tooltip's function description

I'm using VSCode, with Node.js and let's say I have a function:

/**
   * Check if a user is an admin.
   *
   * This function gets a request, and return a result if the current
   * authenticated user is an admin or not.
   *
   * @param req - A request object contains the user's auth permissions.
   * @returns {Boolean}
   */
  static isAdmin(req) {
    return this.isMatch(req, 'admin');
  }

When I hover the function call, I see the following:

Why is the "@returns" empty? I also tried {{Boolean}}, {boolean}, but none of them worked. What is the issue?