Unfortunately the yellow color means status unknown. Wonder why it says started though.
I just found out because the status for apache 2.2 on OS X 10.11.6 is yellow as well. Don’t know if it’s actually working properly.
Here’s what the homebrew-services ServicesCli code says
# For backwards-compatability showing unknown state as started in yellow colour
https://github.com/Homebrew/homebrew-services/blob/6e7ea0cff515df8b5d53a6e3066e16cf5e94d03a/lib/services_cli.rb#L147:L159
EDITS: Update code reference. Thanks @SidOfc