CentOS 6.5
Foreman 1.7.5
ruby193-ruby-1.9.3.484-50.el6.centos.alt.x86_64

Resolve template parameters keep failing if host_parameters_attributes exists.

Started POST "/hosts/template_used?provisioning=build" for 10.100.17.143 at 2015-04-30 04:50:00 -0500
Processing by HostsController#template_used as */*
Parameters: {"utf8"=>"✓", "authenticity_token"=>"x5mJTuyhgKFAWbBzPR1GcbgkMKRTBbRh6eNr0XKIiCI=", "host"=>{"name"=>"aic1-2", "hostgroup_id"=>"", "environment_id"=>"1", "puppet_ca_proxy_id"=>"1", "puppet_proxy_id"=>"1", "puppetclass_ids"=>[""], "managed"=>"t", "progress_report_id"=>"[FILTERED]", "domain_id"=>"3", "realm_id"=>"", "mac"=>"00:15:b2:a5:f3:4d", "subnet_id"=>"2", "ip"=>"172.29.60.26", "interfaces_attributes"=>{"new_interfaces"=>{"_destroy"=>"false", "type"=>"Nic::Managed", "mac"=>"", "identifier"=>"", "name"=>"", "domain_id"=>"", "subnet_id"=>"", "ip"=>"", "managed"=>"1", "virtual"=>"0", "tag"=>"", "attached_to"=>""}}, "architecture_id"=>"1", "operatingsystem_id"=>"5", "medium_id"=>"20", "ptable_id"=>"7", "disk"=>"", "root_pass"=>"[FILTERED]", "host_parameters_attributes"=>{"0"=>{"name"=>"test", "value"=>"[FILTERED]", "hidden_value"=>"[FILTERED]", "_destroy"=>"false", "nested"=>"", "id"=>"301"}}, "is_owned_by"=>"1-Users", "enabled"=>"1", "model_id"=>"", "comment"=>"", "overwrite"=>"false"}, "fakepassword"=>"[FILTERED]", "provisioning"=>"build"}
Rendered common/404.html.erb within layouts/application (1.6ms)
Rendered layouts/base.html.erb (1.5ms)
Completed 404 Not Found in 29ms (Views: 5.3ms | ActiveRecord: 3.6ms)

The way i have fixed it (locally) is adding :host_parameters_attributes to except list in "def template_used"