CI Linter missing tags, only, and environment values

Putting this into https://gitlab.com/ci/lint:

build_template:
  script: ./build.sh
  tags: 
    - dotnet
  only: 
    - test@dude/repo
  environment: testing

Yields:

The tags and only fields are blank, even though they're specified in the YAML. Also, environment doesn't have any output at all.