Emotion compiler not properly working when using "paths" in TypeScript since 13.5.x

Link to the code that reproduces this issue

https://github.com/Itrulia/material-ui-next-nx

To Reproduce

1. npm install && npx nx dev emotion-test

2. Open http://localhost:3000

3. Inspect the HTML output and see .mui-fh6enu{color:pink;}.mui-fh6enu .undefined{color:#f00!important;}.mui-bdz642{color:pink;}

4. Change next to ~13.4.19 and it works.

5. OR move

${StyledPageWebsite} {
    color: #f00 !important;
  }

to the app (for example index.ts) and it works again.

Current vs. Expected behavior

The emotion plugin does not seem to be applied to a library that is referenced via the tsconfig paths. Component selectors by emotion thus don't work properly.

Expected (v13.4.x) vs Now (15.0.0)

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 22.5.0: Thu Jun  8 22:22:20 PDT 2023; root:xnu-8796.121.3~7/RELEASE_ARM64_T6000
  Available memory (MB): 16384
  Available CPU cores: 8
Binaries:
  Node: 22.8.0
  npm: 10.8.2
  Yarn: 1.22.19
  pnpm: N/A
Relevant Packages:
  next: 15.0.1 // Latest available version is detected (15.0.1).
  eslint-config-next: 14.2.3
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.5.4
Next.js Config:
  output: N/A

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

SWC

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

next dev (local), next build (local), next start (local), Vercel (Deployed), Other (Deployed)

Additional context

When changing next to ~13.4.19 it works again, changing it to ~13.5.0 it stopps working.

At first I thought it was this change: https://github.com/vercel/next.js/commit/311eea4c6ab847548d81421a8edbf86ac77341f9

But this is actually setting it to @emotion/react:

console.error(isServerLayer, (jsConfig == null ? void 0 : (_jsConfig_compilerOptions4 = jsConfig.compilerOptions) == null ? void 0 : _jsConfig_compilerOptions4.jsxImportSource) ?? ((compilerOptions == null ? void 0 : compilerOptions.emotion) && !isServerLayer ? "@emotion/react" : "react"))

> false @emotion/react

Start with the linked material-ui-next-nx reproduction and compare Next.js 13.4.19 with 13.5.0 using the listed npm and nx command. Inspect the SWC/Emotion compiler behavior when libraries resolve through tsconfig paths, then verify that the generated HTML no longer contains .undefined and matches the expected output.