Using a field in an unnamed group as title gives an InvalidConfiguration error

[marcelbusch]

Describe the Bug

Heya, I just upgraded from 3.38 -> 3.40 and was presented with an InvalidConfiguration error in my code that was working before. In my collection configuration I have a name field which is wrapped in an unnamed group and is then used as the title of the collection. Reproduction repo is provided, this is already enough to reproduce:

  admin: {
    useAsTitle: 'name',
  },
  fields: [
    {
      type: 'group',
      label: 'unnamed group',
      fields: [
        {
          name: 'name',
          type: 'text',
        },
      ],
    },
  ],

Link to the code that reproduces this issue

https://github.com/marcelbusch/payload-bug-reproduction-useAsTitle-unnamed-group-field

Reproduction Steps

Just spin up the reproduction repo

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

area: core

Environment Info

Binaries:
  Node: 22.16.0
  npm: 11.4.1
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  payload: 3.40.0
  next: 15.3.0
  @payloadcms/email-nodemailer: 3.40.0
  @payloadcms/graphql: 3.40.0
  @payloadcms/next/utilities: 3.40.0
  @payloadcms/payload-cloud: 3.40.0
  @payloadcms/richtext-lexical: 3.40.0
  @payloadcms/translations: 3.40.0
  @payloadcms/ui/shared: 3.40.0
  react: 19.1.0
  react-dom: 19.1.0
Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Thu, 22 May 2025 12:50:32 +0000
  Available memory (MB): 62091
  Available CPU cores: 16