[BUG] Update task fails even though file was not modified externally

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?

When Claude tries to update some files, the Update task fails declaring that the files has been modified externally. But it hasn't. Claude then retries multiple times before falling back to sed-edit. Which usually fails.
I'm running Claude Code 2.0.49

What Should Happen?

the Update task should not report a file to have been modified when it is not the case

Error Messages/Logs

I can see the first file already has my previous edit (line 26 has the malformed path with backslashes removed). Let me fix this    
   file and update the other two with proper forward slashes:

● Update(Maverick-IRSServer\src\Fluxys.Maverick.Irs.Server\Fluxys.Maverick.Irs.Server.csproj)
  ⎿  Error: File has been unexpectedly modified. Read it again before attempting to write it.

● Update(Maverick-IRSServer\src\Fluxys.Maverick.Irs.Server.Host\Fluxys.Maverick.Irs.Server.Host.csproj)
  ⎿  Error: File has been unexpectedly modified. Read it again before attempting to write it.

● Update(Maverick-IRSServer\test\Fluxys.Maverick.Irs.Server.Host.UnitTests\Fluxys.Maverick.Irs.Server.Host.UnitTests.csproj)
  ⎿  Error: File has been unexpectedly modified. Read it again before attempting to write it.

● Update(Maverick-IRSServer\test\Fluxys.Maverick.Irs.Server.Host.UnitTests\Fluxys.Maverick.Irs.Server.Host.UnitTests.csproj)
  ⎿  Error: File has been unexpectedly modified. Read it again before attempting to write it.

● It seems the file monitoring is very sensitive. Let me skip the project reference updates for now and move forward with the
  contract changes. We can come back to the project references if needed. Let me update the todo list and move to the contracts:

Steps to Reproduce

Ask claude code to make changes to existing files.
Wait until it tries.
On a regular basis it will fail.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.49

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_