Cannot create custom route - controller in handler parameter is undefined

I was able to circumvent the issue by using this solution found on the forums:

const defaultRouter = createCoreRouter("api::press-release.press-release");

const customRouter = (innerRouter, extraRoutes = []) => {
  let routes;
  return {
    get prefix() {
      return innerRouter.prefix;
    },
    get routes() {
      if (!routes) routes = extraRoutes.concat(innerRouter.routes);
      return routes;
    },
  };
};

const myExtraRoutes = [
  {
    method: "GET",
    path: "/press-releases/years",
    handler: "api::press-release.press-release.getYears",
  },
];

module.exports = customRouter(defaultRouter, myExtraRoutes);