[BUG] instant auto compact summary isn't updated to reflect most recent work

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

With the new instant auto compact, which I assume is creating compact summaries in the background, it seems to leave out last several messages in the current session, hence failing to capture the full context. This is critical because in the new session, claude starts responding like it has "lost its memory". So I had to open full transcript and manually copy paste last several messages from the previous session to have claude continue from where we actually left off.

Actually, the real issue seems to be that instant auto-compact summary wasn't being updated to reflect most recent work. Basically the summary that appeared instantly when I hit /compact was "stuck" at my past work without being updated to catch up to the latest context.

So it appeared as if last several messages were being lost.

What Should Happen?

Compact should cover full context.

Error Messages/Logs

Steps to Reproduce

Just keep sending messages until instant auto-compact happens.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.70 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_