TypeError: Cannot read property 'properties' of null about docusaurus-lunr-search HOT 3 CLOSED

{
  type: 'element',
  tagName: 'h2',
  properties: {},
  children: [
    {
      type: 'element',
      tagName: 'a',
      properties: [Object],
      children: [],
      position: [Object]
    },
    {
      type: 'text',
      value: 'Jest architectural overview',
      position: [Object]
    },
    {
      type: 'element',
      tagName: 'a',
      properties: [Object],
      children: [Array],
      position: [Object]
    }
  ],
  position: {
    start: { line: 55, column: 1246, offset: 139174 },
    end: { line: 55, column: 1516, offset: 139444 }
  }
}