just a me too, here is the output of production.log

Started POST "/puppetclasses/tsm" for 10.255.1.30 at Wed May 22 10:53:52 +0200 2013
Processing by PuppetclassesController#update as HTML
Parameters: {"utf8"=>"✓", "puppetclass"=>{"name"=>"tsm", "class_params_attributes"=>{"0"=>{"_destroy"=>"false", "description"=>"", "kele"=>"true, false", "path"=>"fqdn\r\nhostgroup\r\nos\r\ndomain", "validator_type"=>"list", "updated_at"=>"1369212805", "lookup_values_ating", "default_value"=>"[FILTERED]", "required"=>"0", "path"=>"fqdn\r\nhostgroup\r\nos\r\ndomain", "validator_type"=>"", "updated_at"=>"erride"=>"0", "required"=>"0", "path"=>"fqdn\r\nhostgroup\r\nos\r\ndomain", "updated_at"=>"1369212805", "lookup_values_attributes"=>"[FI "key_type"=>"string", "default_value"=>"[FILTERED]", "path"=>"fqdn\r\nhostgroup\r\nos\r\ndomain", "validator_type"=>"", "updated_at"=>"m", "environment_filter"=>"", "commit"=>"Submit"}
Rendered lookup_keys/_value.html.erb (3.2ms)
Rendered lookup_keys/_fields.html.erb (18.4ms)
Rendered lookup_keys/_value.html.erb (2.9ms)
Rendered lookup_keys/_fields.html.erb (17.2ms)
Rendered lookup_keys/_value.html.erb (3.2ms)
Rendered lookup_keys/_fields.html.erb (157.1ms)
Rendered lookup_keys/_value.html.erb (3.0ms)
Rendered lookup_keys/_fields.html.erb (13.6ms)
Rendered puppetclasses/_form.html.erb (405.4ms)
Read fragment views/tabs_and_title_records-1 (0.4ms)
Rendered home/_topbar.rhtml (2.9ms)
Rendered home/_user_dropdown.rhtml (1.7ms)
Rendered puppetclasses/edit.html.erb within layouts/application (417.9ms)
Completed 200 OK in 453ms (Views: 412.2ms | ActiveRecord: 212.2ms)

Joseph, any chance this is a dup of #2485 ?