_alternative in _arguments imprime erros, mas ainda funciona

Question

Eu tenho /usr/local/share/zsh/site-functions/_drush

#compdef drush
_arguments \
  "1: :($(/usr/local/bin/firstarg-drush.php))" \
  "2: :_alternative 'arguments: :(php ev scr sql-sync sql-cli sql-query mi)' 'files: :_files'" \
  '*: :_files'

Ao preencher automaticamente o segundo argumento, recebo o autocomplete correto, mas também

_alternative:7: bad option: -J
_alternative:7: bad option: -d
_alternative:7: bad option: -e
_alternative:7: bad option: -f
_alternative:7: bad option: -a
_alternative:7: bad option: -u
_alternative:7: bad option: -l
_alternative:7: bad option: -t
_alternative:7: bad option: --