Since v3.2.0: ReferenceError: CSS is not defined

[janus-reith]

Describe the Bug

v3.2.0 seems to have introduced some error that surfaces on production builds.
Versions prior that version don't have that issue.

While the admin panel seems to work properly, the document is returned with a Status 500 and the server throws:

ReferenceError: CSS is not defined
    at /Users/someuser/Fiddles/test-payload/.next/server/app/(payload)/admin/[[...segments]]/page.js:43:52079
    at Object.ne [as useMemo] (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:20:36390)
    at t.useMemo (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:68:6677)
    at ae (/Users/someuser/Fiddles/test-payload/.next/server/app/(payload)/admin/[[...segments]]/page.js:43:52060)
    at at (/Users/someuser/Fiddles/test-payload/.next/server/app/(payload)/admin/[[...segments]]/page.js:43:53220)
    at nj (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:20:45788)
    at nO (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:20:47563)
    at nN (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:20:65362)
    at nM (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:20:62993)
    at nH (/Users/someuser/Fiddles/test-payload/node_modules/.pnpm/next@15.0.0_react-dom@19.0.0-rc-65a56d0e-20241020_react@19.0.0-rc-65a56d0e-20241020/node_modules/next/dist/compiled/next-server/app-page.runtime.prod.js:20:68775) {
  digest: '1122664388'
}

I also tried switching between nextjs 15 minor versions and react 19 rc versions, made no difference.
I suspect that some code meant for the client gets bundled server side.

Link to the code that reproduces this issue

pnpm dlx create-payload-app

Reproduction Steps

1. pnpm dlx create-payload-app
2. pnpm build
3. pnpm start

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

area: core

Environment Info

Probably not OS specific, happens both on macOS and Linux.

Node.js v22.2.0

Binaries:
  Node: 22.2.0
  npm: 10.7.0
  Yarn: N/A
  pnpm: 8.15.1
Relevant Packages:
  payload: 3.2.0
  next: 15.0.0
  @payloadcms/email-nodemailer: 3.2.0
  @payloadcms/graphql: 3.2.0
  @payloadcms/next/utilities: 3.2.0
  @payloadcms/payload-cloud: 3.2.0
  @payloadcms/richtext-lexical: 3.2.0
  @payloadcms/translations: 3.2.0
  @payloadcms/ui/shared: 3.2.0
  react: 19.0.0-rc-65a56d0e-20241020
  react-dom: 19.0.0-rc-65a56d0e-20241020

[github-actions]

Please add a reproduction in order for us to be able to investigate.

Depending on the quality of reproduction steps, this issue may be closed if no reproduction is provided.

Why was this issue marked with the invalid-reproduction label?

To be able to investigate, we need access to a reproduction to identify what triggered the issue. We prefer a link to a public GitHub repository created with create-payload-app@beta -t blank or a forked/branched version of this repository with tests added (more info in the reproduction-guide).

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I added a link, why was it still marked?

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Useful Resources

• Reproduction Guide
• Contributing to Payload

[AlessioGr]

Fixed! Here's a canary with the fix if you don't wanna wait for the next release: 3.2.2-canary.a11698b