Mobile Remote truncates existing Windows desktop thread history while local rollout stays complete #41707

Summary

After opening existing Codex Desktop tasks through ChatGPT mobile Remote, several desktop threads became the newest tasks but their visible history regressed to an early state. The local rollout JSONL files still contain the complete conversations, completed turns, and final answers.

This was observed on 2026-08-30 across a group of tasks. Opening the tasks through mobile Remote is the common preceding action; I cannot prove causality, but the regression appeared immediately afterward.

Environment

• Host OS: Windows 10 Pro 64-bit, build 10.0.19042
• Codex Desktop package: OpenAI.Codex_26.825.6671.0_x64
• Desktop executable version: 151.0.7922.174
• Bundled Codex CLI: 0.151.0-alpha.7.2 (one older affected task was created with 0.150.0-alpha.12.2)
• Mobile client: ChatGPT app using Remote (phone OS/build not recorded)
• The affected tasks were originally created and progressed on Codex Desktop, not on mobile

Steps to reproduce

1. Start a task in Codex Desktop on Windows.
2. Complete multiple user/assistant turns, including long-running work and final answers.
3. Open the same host/task from the ChatGPT mobile app using Remote while the mobile client does not load the complete history.
4. Return to Codex Desktop and open the task.
5. The task is recent, but only the early portion of the history is visible. Reopening does not expose additional pages.

Expected behavior

Remote should preserve and continue the complete existing desktop conversation. A client that has only a partial view must not overwrite or become authoritative over a longer server/local history.

Actual behavior

The desktop-visible/backend-readable task history is truncated, while the local rollout remains complete.

Two confirmed examples:

• Thread 01a051f6-f060-7581-9a57-4ca76c006351: local rollout contains 4 meaningful user messages, 5 task_complete events, and 4 non-empty final answers. The app currently returns only the first interrupted turn and reports hasMore: false.
• Thread 01a04a2f-f61f-76f0-8b98-c8efcf44c5ad: local rollout contains 12 meaningful user messages, 12 task_complete events, and 11 non-empty final answers. The app currently returns only 3 turns and reports hasMore: false.

The local session_index.jsonl timestamps are also stale relative to the final JSONL events. For the first example, the index timestamp remains near task creation even though the rollout continues hours later.

Raw rollouts are not attached because they contain source code, local paths, and project data. Sanitized diagnostics can be provided privately.

Impact

This looks like conversation data loss in the UI even though the raw local data survives. It can make the user and agent resume from stale context, duplicate completed research, or undo already-finished work. There is currently no supported reindex/recovery action in the desktop UI.

Possibly related

• Android Remote chats started on a Mac host do not appear in desktop app history #37385
• Android Remote Control does not load host thread history (no thread/list requests observed) #22762
• Windows Desktop: conversations disappear from UI even though JSONL sessions still exist; add first-party recovery/reindex tool #40779

Those reports cover missing Remote/desktop history or JSONL data not appearing in the UI. This report is specifically about an existing desktop-origin thread being present but regressing to an early, incomplete history after mobile Remote access.