Current turn changes are intermittently missing from chat responses

## Type of issue

Bug

## Description

The **View Current Turn Changes** information/pill is intermittently missing after an agent turn that changed files. This has been happening recently in VS Code Insiders.

The turn still completes and shows its response summary, but there is no current-turn changes entry to inspect the files modified by that turn. Multiple users have observed the issue, and this information is useful for reviewing and understanding agent changes.

## Expected behavior

After a turn changes files, the **View Current Turn Changes** entry is consistently shown.

## Actual behavior

The entry is sometimes absent even though the turn made changes.

## Version

Version: 1.137.0-insider (Universal)
Commit: 9aaf490382bd0ecdd72db3d2f308cdf1fdc6a79d
Date: 2026-09-08T10:45:51Z
Electron: 42.10.0
ElectronBuildId: 15109253
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
@github/copilot: 1.0.84-canary.70.gdb75d0d.unsigned
@github/copilot-sdk: 1.0.13-preview.4
OS: Darwin arm64 25.6.0