CI (audit) reports a missing alias despite an alias already existing

[javian]

Please always follow these steps:

• Confirmed this is a problem with running a brew command and not brew installing or the post-install behaviour of one or more formulae? If it's a formulae-specific problem please file this issue at https://github.com/Homebrew/homebrew-core/issues/new
• Ran brew update and retried your prior step?
• Ran brew doctor, fixed all issues and retried your prior step?

In a recent CI build on the homebrew-php tap https://jenkins.brew.sh/job/Homebrew%20PHP%20Pull%20Requests/393/version=sierra/console we see the following

Error: 2 problems in 1 formula
homebrew/php/composer:
  * Formula has other versions so create a versioned alias:
      cd /usr/local/Homebrew/Library/Taps/homebrew/homebrew-php/Aliases
      ln -s ../Formula/composer.rb composer@1.4
  * Formula has invalid versioned aliases:
      composer@1.4

This error is however not reflecting reality since the alias already exists as you can see here https://github.com/Homebrew/homebrew-php/tree/master/Aliases

The issue has appeared once before in #2657 and was fixed at the time. @ilovezfs (on slack) blamed commit 43c8223 this time but I'm not able to verify that since I don't understand enough of the code.