Rails new をバージョン指定で実行した際のエラー check_version_conflict が解決できない

Question

Rails new をRailsのバージョンを指定して実行すると下記のようなエラーが発生します．バージョンを指定しなければアプリは作成されます．
見たことの無いエラーでググっても同様のエラーを見つけることができませんでした．
よろしくお願い致します．

$ rails _5.0.0.1_ new sample_app
~/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/specification.rb:2278:in `check_version_conflict': can't activate activesupport-5.0.1, already activated activesupport-5.0.0.1 (Gem::LoadError)
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/specification.rb:1404:in `activate'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:89:in `block in require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:88:in `each'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:88:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/concurrent-ruby-1.0.4/lib/concurrent.rb:15:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/logger_silence.rb:3:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support/logger.rb:1:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/activesupport-5.0.0.1/lib/active_support.rb:27:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/generators.rb:6:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/commands/application.rb:1:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/lib/rails/cli.rb:14:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/ueki/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/railties-5.0.0.1/exe/rails:9:in `<top (required)>'
	from /Users/ueki/.rbenv/versions/2.3.1/bin/rails:23:in `load'
	from /Users/ueki/.rbenv/versions/2.3.1/bin/rails:23:in `<main>'

補足

$ rbenv versions
  system
  2.0.0-p648
* 2.3.1 (set by /Users/ueki/.rbenv/version)
  2.4.0
$ rails -v
Rails 5.0.1

Answer 1

Gemでバージョンが複数入っているものがあり，それが競合していたようです．
ひとまずインストールしていたGemを全て削除して，Railsを再インストールしたら動くようになりました．