The process '/usr/bin/tar' failed with exit code 1 -- file changed as we read it

There is not a clear approach on how to work around this or force it to tar up the files.

I've tried force killing the running process before calling actions/cache/save and it complains files are being changed. I don't understand how best to debug this but seems like with the compression program used.

There needs to be a verbose option to see what's happening under the hood to better understand why this fails the workflow.

/usr/bin/tar --posix -cf cache.tzst --exclude cache.tzst -P -C /home/github/actions-runner/_work/artifacts --files-from manifest.txt --use-compress-program zstdmt
/usr/bin/tar: artifacts/: file changed as we read it
Warning: Failed to save: "/usr/bin/tar" failed with error: The process '/usr/bin/tar' failed with exit code 1
Warning: Cache save failed.

Configuration used:

    - name: Save ${{ matrix.target }} Corpus
      if: always()
      uses: actions/cache/save@v4.2.0
      with:
        path: ${{ github.workspace }}/artifacts
        key: ${{ matrix.target }}-corpus-${{ github.run_id }}

Start by reproducing the actions/cache/save workflow with the shown path and command, then inspect the tar output around manifest.txt and the reported artifacts/ change. Compare the failure with the requested verbose diagnostics and define done as making the cache-save failure explainable or reliably handled when files change during archiving.