Regex error with delete-obsolete

[hatton]

yarn crowdin upload sources --delete-obsolete gives

$ crowdin upload sources --delete-obsolete
[OK] Fetching project info 
[ERROR] Unmatched closing ')' near index 10
^docs\(.+\\)?[^/]+\.[^/]+$
          ^

My crowdin.yml has

    {
      "source": "/docs/**/*.*",
      "translation": /i18n/%two_letters_code%/docusaurus-plugin-content-docs/current/**/%original_file_name%,
      "skip_untranslated_files": true,
      "ignore": ["/**/*.png", "/**/*.jpg", "/**/*.gif"],
    },

I am using Windows, bash shell. project_id is 515854. @crowdin/cli version 3.8.1