bundler 1.0.14 on ruby 1.9.2p180
If I call Bundler.setup(:default), and then call Bundler.setup(:default, :some_additional_group), and then try to require a gem in default, I get a "no such file to load" error.
If you look at the attached gist, and run bundler_require.rb, it will require mocha ok, but break when it tries to require nokogiri.
Let me know if you need any more info. =)