[BUG] Claude don't read ENTIRE mention file anymore, if file read early.

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?

If the agent has already read part of the file, say lines 1-10, when @file is mentioned, the agent no longer reads the entire file.

What Should Happen?

The agent MUST read whole file if mentioned

Error Messages/Logs

Steps to Reproduce

..

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

1.0.120

Claude Code Version

1.0.120

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_