Gatsby using Suspense that fails to build

index.js

import React, { Suspense, lazy } from "react"
import { graphql, useStaticQuery } from "gatsby"
import Layout from "../components/Layout"

const importBlock = blockName =>
  lazy(() => import(`../components/blocks/${blockName}/index.js`))

export default () => {
  const { allDirectory } = useStaticQuery(graphql`
    {
      allDirectory(filter: { relativePath: { ne: "" } }) {
        edges {
          node {
            relativePath
            id
          }
        }
      }
    }
  `)

  const blocks = allDirectory.edges.map(({ node }) => {
    const Block = importBlock(node.relativePath)
    return <Block key={node.id} />
  })

  return (
    <Layout>
      <Suspense fallback={"loading"}>{blocks}</Suspense>
    </Layout>
  )
}