[macOS Desktop] A single Codex task permanently enters systemError and in-app feedback also fails with “Bad Request”

Codex version

• ChatGPT desktop app: 26.818.41509
• Bundled Codex: codex-cli 0.149.0-alpha.4.1
• Platform: macOS

Issue

A single Codex task entered a permanent systemError state. Every subsequent message returns:

{"detail":"Bad Request"}

The task cannot recover after restarting or sending short messages. The in-app feedback action also fails, so I cannot generate or submit a feedback session ID from the affected task.

Affected task ID:

01a024fe-b891-70b2-8e05-656d2c22d36f

Steps to reproduce

1. Run a long Swift/iOS development task involving file edits, simulator screenshots, and tool output.
2. The task eventually returns {"detail":"Bad Request"}.
3. Send a short follow-up message such as “网络问题？” or “刷新”.
4. The same error is returned immediately.
5. Try to submit feedback from the affected task.
6. Feedback submission also fails.

Expected behavior

The task should either continue normally or provide a recoverable error with a working feedback/reporting mechanism.

Actual behavior

The affected task remains permanently unusable. Other Codex tasks in the same desktop app continue working normally.

Additional information

• Local source-code changes from the task were preserved.
• No build or shell process remained running after the failure.
• The local session transcript had grown to approximately 53 MB and contained substantial embedded screenshot/tool output.
• The task was still below the model context-window limit, so this appears more consistent with a task-state serialization or backend request-validation failure than a normal context overflow. This is an inference, not a confirmed root cause.
• Screenshot attached.