Drafts autosave: Error building form state - Cannot read properties of null (reading '_id')

[Collexi-Dev]

Describe the Bug

When editing documents, i.e. adding / removing blocks or items, if autosave is enabled occasionally the following error occurs:

[16:49:55] ERROR: There was an error building form state
    err: {
      "type": "TypeError",
      "message": "Cannot read properties of null (reading '_id')",
      "stack":
          TypeError: Cannot read properties of null (reading '_id')
              at Object.updateOne (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]_@[email protected]_@aws-sdk+client-sso-oidc@_7gkyaxq7c2tb6culk4azy6wsei/node_modules/@payloadcms/db-mongodb/dist/updateOne.js:55:24)
              at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
              at async handleFormStateLocking (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected]_r_h5irrt4qzojdy236los5gpcbcq/node_modules/@payloadcms/ui/dist/utilities/handleFormStateLocking.js:67:11)
              at async buildFormState (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected]_r_h5irrt4qzojdy236los5gpcbcq/node_modules/@payloadcms/ui/dist/utilities/buildFormState.js:168:25)
              at async buildFormStateHandler (webpack-internal:///(rsc)/./node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected]_r_h5irrt4qzojdy236los5gpcbcq/node_modules/@payloadcms/ui/dist/utilities/buildFormState.js:56:17)
              at async /PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-page.runtime.dev.js:157:2088
              at async handleAction (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-page.runtime.dev.js:156:21940)
              at async renderToHTMLOrFlightImpl (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/compiled/next-server/app-page.runtime.dev.js:161:22397)
              at async doRender (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:1574:34)
              at async responseGenerator (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:1822:28)
              at async DevServer.renderToResponseWithComponentsImpl (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:1832:28)
              at async DevServer.renderPageComponent (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:2259:24)
              at async DevServer.renderToResponseImpl (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:2297:32)
              at async DevServer.pipeImpl (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:959:25)
              at async NextNodeServer.handleCatchallRenderRequest (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/next-server.js:281:17)
              at async DevServer.handleRequestImpl (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/base-server.js:853:17)
              at async /PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/dev/next-dev-server.js:371:20
              at async Span.traceAsyncFn (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/trace/trace.js:153:20)
              at async DevServer.handleRequest (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/dev/next-dev-server.js:368:24)
              at async invokeRender (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/router-server.js:230:21)
              at async handleRequest (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/router-server.js:408:24)
              at async requestHandlerImpl (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/router-server.js:432:13)
              at async Server.requestListener (/PayloadCMS-Testing/20250114-latest-template/node_modules/.pnpm/[email protected][email protected][email protected][email protected][email protected]/node_modules/next/dist/server/lib/start-server.js:146:13)
    }

The error makes it so that when you're inserting blocks or items they sometimes stay in the loading state because of the error and you need to remove and re-add it which is rather annoying to explain to a client.

When autosave is disabled the issue goes away. Not sure if it's MongoDB specific or not.

Link to the code that reproduces this issue

https://github.com/Collexi-Dev/test-payload-3-stable

Reproduction Steps

1. Clone latest website template
2. Set up with MongoDB Atlas
3. Repeatedly add/remove a block or item from an array in the admin panel until error occurs

Which area(s) are affected? (Select all that apply)

area: core

Environment Info

Binaries:
  Node: 20.13.1
  npm: 10.5.2
  Yarn: 1.22.22
  pnpm: 9.12.2
Relevant Packages:
  payload: 3.17.1
  next: 15.1.4
  @payloadcms/db-mongodb: 3.17.1
  @payloadcms/email-nodemailer: 3.17.1
  @payloadcms/graphql: 3.17.1
  @payloadcms/live-preview: 3.17.1
  @payloadcms/live-preview-react: 3.17.1
  @payloadcms/next/utilities: 3.17.1
  @payloadcms/payload-cloud: 3.17.1
  @payloadcms/plugin-form-builder: 3.17.1
  @payloadcms/plugin-nested-docs: 3.17.1
  @payloadcms/plugin-redirects: 3.17.1
  @payloadcms/plugin-search: 3.17.1
  @payloadcms/plugin-seo: 3.17.1
  @payloadcms/richtext-lexical: 3.17.1
  @payloadcms/translations: 3.17.1
  @payloadcms/ui/shared: 3.17.1
  react: 19.0.0
  react-dom: 19.0.0
Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.2.0: Fri Dec  6 19:02:12 PST 2024; root:xnu-11215.61.5~2/RELEASE_ARM64_T6031
  Available memory (MB): 36864
  Available CPU cores: 14