bug: 4.39 Rollup Plugin Error with Mixins and Spec + e2e test

[kyleMessnerLillyContractor]

Prerequisites

• I have read the Contributing Guidelines.
• I agree to follow the Code of Conduct.
• I have searched for existing issues that already report this problem, without success.

Stencil Version

4.39.0

Current Behavior

Running just --e2e tests passes
Running just --spec tests passes
Running --spec --e2e tests fails

Expected Behavior

Running unit tests with both --e2e and --spec flags together works.

System Info

System: node 22.14.0
    Platform: darwin (25.1.0)
   CPU Model: Apple M4 Pro (12 cpus)
    Compiler: /Users/user/Documents/stencil-issue/node_modules/@stencil/core/compiler/stencil.js
       Build: 1765277402
     Stencil: 4.39.0 🎭
  TypeScript: 5.8.3
      Rollup: 4.34.9
      Parse5: 7.2.1
      jQuery: 4.0.0-pre
      Terser: 5.37.0

Steps to Reproduce

npm install
npm run test-1 (passes)
npm run test-2 (passes)
npm run test-3 (fails)

Code Reproduction URL

https://github.com/kyleMessnerLillyContractor/stencil-issue/tree/issue-2

Additional Information

No response