Why can modules.data be undefined here?

export const Route = createFileRoute('/_auth/gameserver/$gameServerId/modules')({
  loader: async ({ params, context }) => {
    const [modules, moduleInstallations] = await Promise.all([
      context.queryClient.ensureQueryData(modulesQueryOptions()),
      context.queryClient.ensureQueryData(gameServerModuleInstallationsOptions(params.gameServerId)),
    ]);
    return { modules: modules, installations: moduleInstallations };
  },
  component: Component,
  pendingComponent: () => (
    <CardList>
      {Array.from({ length: 10 }).map((_, i) => (
        <Skeleton key={i} variant="rectangular" height="100%" width="100%" />
      ))}
    </CardList>
  ),
});

export function Component() {
  const loaderData = Route.useLoaderData();
  const { gameServerId } = Route.useParams();

  const { data: installations } = useSuspenseQuery({
    ...gameServerModuleInstallationsOptions(gameServerId),
    initialData: loaderData.installations,
  });
  const { data: modules } = useSuspenseQuery({
    ...modulesQueryOptions(),
    initialData: loaderData.modules,
  });

  const mappedModules = modules.data.map((mod) => {
     ...
  });

export const Route = createFileRoute('/_auth/gameserver/$gameServerId/modules')({
  loader: async ({ params, context }) => {
    const [modules, moduleInstallations] = await Promise.all([
      context.queryClient.ensureQueryData(modulesQueryOptions()),
      context.queryClient.ensureQueryData(gameServerModuleInstallationsOptions(params.gameServerId)),
    ]);
    return { modules: modules, installations: moduleInstallations };
  },
  component: Component,
  pendingComponent: () => (
    <CardList>
      {Array.from({ length: 10 }).map((_, i) => (
        <Skeleton key={i} variant="rectangular" height="100%" width="100%" />
      ))}
    </CardList>
  ),
});

export function Component() {
  const loaderData = Route.useLoaderData();
  const { gameServerId } = Route.useParams();

  const { data: installations } = useSuspenseQuery({
    ...gameServerModuleInstallationsOptions(gameServerId),
    initialData: loaderData.installations,
  });
  const { data: modules } = useSuspenseQuery({
    ...modulesQueryOptions(),
    initialData: loaderData.modules,
  });

  const mappedModules = modules.data.map((mod) => {
     ...
  });