bundle exec middleman server で bundler: failed to load command: middleman エラーが出てしまう

表題の通り、middleman でローカルサーバーを起動させようとすると、エラーが出てしまいます。
色々試してみたのですが、解決できずご助言いただけますと幸いです。

前提

bundle install --path vendor/bundle でプロジェクト固有のbundleを入れた認識
which bundle で /Users/home/.rbenv/shims/bundleとなってしまうので、上でインストールしたものが正しく指定されていない？
which ruby も /Users/home/.rbenv/shims/ruby

やりたいこと

middleman でのローカルサーバー起動

エラー

== The Middleman is loading
== Sprockets will render css with SassC
bundler: failed to load command: middleman (/Users/home/git/reponame/vendor/bundle/ruby/2.5.0/bin/middleman)
NoMethodError: undefined method `except' for nil:NilClass
Did you mean?  exec
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/core_extensions/collections/lazy_step.rb:37:in `value'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/core_extensions/collections/lazy_step.rb:23:in `value'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/core_extensions/collections.rb:105:in `block (2 levels) in manipulate_resource_list'
  /Users/home/.rbenv/versions/2.5.3/lib/ruby/2.5.0/set.rb:338:in `each_key'
  /Users/home/.rbenv/versions/2.5.3/lib/ruby/2.5.0/set.rb:338:in `each'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/core_extensions/collections.rb:104:in `block in manipulate_resource_list'
  /Users/home/.rbenv/versions/2.5.3/lib/ruby/2.5.0/monitor.rb:226:in `mon_synchronize'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/core_extensions/collections.rb:87:in `manipulate_resource_list'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/contracts-0.13.0/lib/contracts/method_reference.rb:43:in `send_to'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/contracts-0.13.0/lib/contracts/call_with.rb:76:in `call_with'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/contracts-0.13.0/lib/contracts/method_handler.rb:138:in `block in redefine_method'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/sitemap/store.rb:234:in `block (4 levels) in ensure_resource_list_updated!'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/activesupport-5.0.7.2/lib/active_support/notifications.rb:166:in `instrument'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/util.rb:21:in `instrument'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/sitemap/store.rb:232:in `block (3 levels) in ensure_resource_list_updated!'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/hamster-3.0.0/lib/hamster/vector.rb:1316:in `each'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/hamster-3.0.0/lib/hamster/vector.rb:1316:in `traverse_depth_first'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/hamster-3.0.0/lib/hamster/vector.rb:431:in `each'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/sitemap/store.rb:231:in `block (2 levels) in ensure_resource_list_updated!'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/activesupport-5.0.7.2/lib/active_support/notifications.rb:166:in `instrument'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/util.rb:21:in `instrument'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/sitemap/store.rb:224:in `block in ensure_resource_list_updated!'
  /Users/home/.rbenv/versions/2.5.3/lib/ruby/2.5.0/monitor.rb:226:in `mon_synchronize'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/sitemap/store.rb:221:in `ensure_resource_list_updated!'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/sitemap/extensions/on_disk.rb:21:in `ready'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/callback_manager.rb:57:in `instance_exec'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/callback_manager.rb:57:in `block in execute'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/hamster-3.0.0/lib/hamster/vector.rb:1316:in `each'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/hamster-3.0.0/lib/hamster/vector.rb:1316:in `traverse_depth_first'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/hamster-3.0.0/lib/hamster/vector.rb:431:in `each'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/callback_manager.rb:57:in `execute'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/contracts-0.13.0/lib/contracts/method_reference.rb:43:in `send_to'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/contracts-0.13.0/lib/contracts/call_with.rb:76:in `call_with'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/contracts-0.13.0/lib/contracts/method_handler.rb:138:in `block in redefine_method'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/callback_manager.rb:28:in `block in install_methods!'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/application.rb:309:in `initialize'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/preview_server.rb:144:in `new'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/preview_server.rb:144:in `initialize_new_app'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-core-4.3.5/lib/middleman-core/preview_server.rb:34:in `start'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-cli-4.3.5/lib/middleman-cli/server.rb:53:in `server'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/command.rb:27:in `run'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:126:in `invoke_command'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:133:in `block in invoke_all'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:133:in `each'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:133:in `map'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:133:in `invoke_all'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/group.rb:232:in `dispatch'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:115:in `invoke'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor.rb:40:in `block in register'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/command.rb:27:in `run'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:126:in `invoke_command'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor.rb:387:in `dispatch'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/thor-0.20.3/lib/thor/base.rb:466:in `start'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/gems/middleman-cli-4.3.5/bin/middleman:70:in `<top (required)>'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/bin/middleman:23:in `load'
  /Users/home/git/reponame/vendor/bundle/ruby/2.5.0/bin/middleman:23:in `<top (required)>'