1. Add the following code to an init.el:

   (use-package gnus
     :ensure nil
     :custom
     (gnus-logo-color-style 'neutral))

2. Start emacs, M-x gnus, and notice that the logo does not change to
the neutral gray colors.

This does not seem to happen when using the Customization interface
which puts `custom-set-variables' in your init.el:

      (custom-set-variables
       '(gnus-logo-color-style 'neutral))


I'm not sure if this is related to use-package's :custom keyword, but I
have not come across this issue while using any other built-in emacs
packages.

Please see the attached patch file for a possible fix and minor
improvement.

Thanks,
Trevor