流星和反应地图恢复未定义状态，我知道数据在那里，但尽管等待isLoading，但仍在加载

我有以下代码，将LeadsBuilder道具传递给LeadBuilderSingle组件。它在对象中有一个数组，我访问该数组并尝试在其上进行映射，但返回未定义。数据正在等待，并且我正在使用isLoading，所以我不确定是什么导致此错误。它在第一次加载时加载，但是在页面刷新时却给我未定义的信息。

import React, { useState, useEffect } from "react";
import Dasboard from "./Dashboard";
import { Container } from "../styles/Main";
import { LeadsBuilderCollection } from "../../api/LeadsCollection";
import { LeadBuilderSingle } from "../leads/LeadBuilderSingle";
import { useTracker } from "meteor/react-meteor-data";

const LeadCategoriesAdd = ({ params }) => {
  const { leadsBuilder, isLoading } = useTracker(() => {
    const noDataAvailable = { leadsBuilder: [] };

    if (!Meteor.user()) {
      return noDataAvailable;
    }

    const handler = Meteor.subscribe("leadsBuilder");

    if (!handler.ready()) {
      return { ...noDataAvailable, isLoading: true };
    }

    const leadsBuilder = LeadsBuilderCollection.findOne({ _id: params._id });
    return { leadsBuilder };
  });

  return (
    <Container>
      <Dasboard />
      <main className="">
        {isLoading ? (
          <div className="loading">loading...</div>
        ) : (
          <>
            <LeadBuilderSingle key={params._id} lead={leadsBuilder} />
          </>
        )}
      </main>
    </Container>
  );
};

export default LeadCategoriesAdd;

import React from "react";

export const LeadBuilderSingle = ({ lead, onDeleteClick }) => {
  console.log(lead);

  return (
    <>
      <li>{lead.type}</li>
      {lead.inputs.map((input, i) => {
        return <p key={i}>{input.inputType}</p>;
      })}
    </>
  );
};

FlowRouter.route("/leadCategories/:_id", {
  name: "leadeBuilder",
  action(params) {
    mount(App, {
      content: <LeadCategoriesAdd params={params} />,
    });
  },
});