Localized templates are not served by middleman server

I follow the guide on “Localizing Entire Templates” and create two files under /source:

index.en.html.erb
index.zh-TW.html.erb

Middleman build them correctly:

$ middleman build
   identical  build/index.zh-TW.html
   identical  build/index.en.html
   identical  build/index.html
   identical  build/zh-TW/index.html

But when I run ‘middleman server’ and connect to ‘http://0.0.0.0:4567’, the index.html is not served. Neither does ‘http://0.0.0.0:4567/zh-TW/index.html

Did I do anything wrong or it is a bug ?

By the way, ‘middleman build’ create two extra files which are not necessary:

   identical  build/index.zh-TW.html
   identical  build/index.en.html

What does your config.rb look like?

Your question indeed reminds me to check where i18n module is activated. Now I move i18n module to global settings and it works now. Below is the original one, which activate i18n only during building.
Thanx for your suggestion.

set :css_dir, 'stylesheets'
set :js_dir, 'javascripts'
set :images_dir, 'images'

# Build-specific configuration
configure :build do
  activate :i18n, :mount_at_root => :en
end

I am having this same problem, did you find a solution/cause to this?

Many thanks,
Mark