This post should not appear in the search index because it has the following YAML Front Matter:

search: false

Note: search: false only works to exclude posts when using Lunr as a search provider.

To exclude files when using Algolia as a search provider add an array to algolia.files_to_exclude in your _config.yml. For more configuration options be sure to check their full documentation.

algolia:
  # Exclude more files from indexing
  files_to_exclude:
    - index.html
    - index.md
    - excluded-file.html
    - _posts/2017-11-28-post-exclude-search.md
    - subdirectory/*.html