flake: experimental_csp_allow_list_spec system-tests-chrome exit code 1 despite passing Cypress tests #34265

Summary

Pipeline 83746 for develop commit 061d5a12f8b59ef892216a0ab7279c2597ad7637 failed system-tests-chrome with:

e2e experimentalCspAllowList experimentalCspAllowList=true strips out ['script-src-elem', 'script-src', 'default-src', 'form-action'] directives [chrome]:
  AssertionError: Process errored: Exit code 1: expected 1 to equal +0

Details

• Job: system-tests-chrome (build 3775502) in linux-x64 workflow
• Merged PR: chore: upgrade x86_64 CircleCI resource classes to gen2 #34253 (CircleCI x86_64 resource class gen2 upgrade) — only touches .circleci/ config; unrelated to CSP tests
• Cypress spec output: with_allow_list_true.cy.ts reported 4 passing, 0 failing before the system-test harness asserted exit code 0
• Platform workflows: linux-arm64, darwin-x64, darwin-arm64, windows all succeeded; only linux-x64 failed
• Prior develop pipelines 83738 and 83727 passed system-tests-chrome

Log excerpt

The inner Cypress run finished successfully:

│ ✔  with_allow_list_true.cy.ts               00:04        4        4        -        -        - │
  ✔  All specs passed!                        00:04        4        4        -        -        -

But the system-test wrapper failed on exit code verification.

A separate subtest (form_action_with_allow_list_custom.cy.ts / fails on inline form action) also hit a pageLoadTimeout (1000ms) flake in the same job batch, though the mocha failure recorded was for the first test above.

Request

Investigate why @packages/server can return exit code 1 when the Cypress spec reports all tests passing, and whether experimental_csp_allow_list_spec.ts needs additional retries or timeout hardening in CI.