Heroku ruby production error -

i had error occurred in production , wondering have heroku setup or app?

this error :

argumenterror: invalid %-encoding (\k9Λ|�x� ��(%0i0�z���-g�뒨ڼ) vendor/ruby-2.0.0/lib/ruby/2.0.0/uri/common.rb:898:in decode_www_form_component vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/utils.rb:41:in unescape vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/utils.rb:94:in block (2 levels) in parse_nested_query vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/utils.rb:94:in map vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/utils.rb:94:in block in parse_nested_query vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/utils.rb:93:in each vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/utils.rb:93:in parse_nested_query vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/request.rb:332:in parse_query vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/http/request.rb:275:in parse_query vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/request.rb:209:in post vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/http/request.rb:237:in post vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/http/parameters.rb:10:in parameters vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/http/filter_parameters.rb:31:in filtered_parameters vendor/bundle/ruby/2.0.0/gems/newrelic_rpm-3.6.2.96/lib/new_relic/agent/instrumentation/rails3/action_controller.rb:37:in process_action vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/abstract_controller/base.rb:121:in process vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/abstract_controller/rendering.rb:45:in process vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_controller/metal.rb:203:in dispatch vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_controller/metal/rack_delegation.rb:14:in dispatch vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_controller/metal.rb:246:in block in action vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/routing/route_set.rb:73:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/routing/route_set.rb:73:in dispatch vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/routing/route_set.rb:36:in call vendor/bundle/ruby/2.0.0/gems/journey-1.0.4/lib/journey/router.rb:68:in block in call vendor/bundle/ruby/2.0.0/gems/journey-1.0.4/lib/journey/router.rb:56:in each vendor/bundle/ruby/2.0.0/gems/journey-1.0.4/lib/journey/router.rb:56:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/routing/route_set.rb:608:in call vendor/bundle/ruby/2.0.0/gems/omniauth-1.1.4/lib/omniauth/strategy.rb:184:in call! vendor/bundle/ruby/2.0.0/gems/omniauth-1.1.4/lib/omniauth/strategy.rb:164:in call vendor/bundle/ruby/2.0.0/gems/omniauth-1.1.4/lib/omniauth/builder.rb:49:in call vendor/bundle/ruby/2.0.0/gems/newrelic_rpm-3.6.2.96/lib/new_relic/rack/error_collector.rb:12:in call vendor/bundle/ruby/2.0.0/gems/newrelic_rpm-3.6.2.96/lib/new_relic/rack/agent_hooks.rb:18:in call vendor/bundle/ruby/2.0.0/gems/newrelic_rpm-3.6.2.96/lib/new_relic/rack/browser_monitoring.rb:16:in call vendor/bundle/ruby/2.0.0/gems/request_store-1.0.5/lib/request_store/middleware.rb:9:in call vendor/bundle/ruby/2.0.0/gems/client_side_validations-3.2.5/lib/client_side_validations/middleware.rb:21:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/best_standards_support.rb:17:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/etag.rb:23:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/conditionalget.rb:25:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/head.rb:14:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/params_parser.rb:21:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/flash.rb:242:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/session/abstract/id.rb:210:in context vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/session/abstract/id.rb:205:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/cookies.rb:341:in call vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.14/lib/active_record/query_cache.rb:64:in call vendor/bundle/ruby/2.0.0/gems/activerecord-3.2.14/lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/callbacks.rb:28:in block in call vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.14/lib/active_support/callbacks.rb:405:in run_1231007684488043729__call__3041923490950210072__callbacks vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.14/lib/active_support/callbacks.rb:405:in __run_callback vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.14/lib/active_support/callbacks.rb:385:in run_call_callbacks vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.14/lib/active_support/callbacks.rb:81:in run_callbacks vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/callbacks.rb:27:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/remote_ip.rb:31:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/debug_exceptions.rb:16:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/show_exceptions.rb:56:in call vendor/bundle/ruby/2.0.0/gems/railties-3.2.14/lib/rails/rack/logger.rb:32:in call_app vendor/bundle/ruby/2.0.0/gems/railties-3.2.14/lib/rails/rack/logger.rb:16:in block in call vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.14/lib/active_support/tagged_logging.rb:22:in tagged vendor/bundle/ruby/2.0.0/gems/railties-3.2.14/lib/rails/rack/logger.rb:16:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/request_id.rb:22:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/methodoverride.rb:21:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/runtime.rb:17:in call vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.14/lib/active_support/cache/strategy/local_cache.rb:72:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/lock.rb:15:in call vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.14/lib/action_dispatch/middleware/static.rb:63:in call vendor/bundle/ruby/2.0.0/gems/rack-cache-1.2/lib/rack/cache/context.rb:136:in forward vendor/bundle/ruby/2.0.0/gems/rack-cache-1.2/lib/rack/cache/context.rb:245:in fetch vendor/bundle/ruby/2.0.0/gems/rack-cache-1.2/lib/rack/cache/context.rb:185:in lookup vendor/bundle/ruby/2.0.0/gems/rack-cache-1.2/lib/rack/cache/context.rb:66:in call! vendor/bundle/ruby/2.0.0/gems/rack-cache-1.2/lib/rack/cache/context.rb:51:in call vendor/bundle/ruby/2.0.0/gems/railties-3.2.14/lib/rails/engine.rb:484:in call vendor/bundle/ruby/2.0.0/gems/railties-3.2.14/lib/rails/application.rb:231:in call vendor/bundle/ruby/2.0.0/gems/railties-3.2.14/lib/rails/railtie/configurable.rb:30:in methodmissing vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/urlmap.rb:64:in block in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/urlmap.rb:49:in each vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/urlmap.rb:49:in call vendor/bundle/ruby/2.0.0/gems/rack-1.4.5/lib/rack/deflater.rb:13:in call vendor/bundle/ruby/2.0.0/gems/rack-rewrite-1.3.3/lib/rack/rewrite.rb:20:in call vendor/bundle/ruby/2.0.0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:552:in process_client vendor/bundle/ruby/2.0.0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:632:in worker_loop vendor/bundle/ruby/2.0.0/gems/newrelic_rpm-3.6.2.96/lib/new_relic/agent/instrumentation/unicorn_instrumentation.rb:22:in call vendor/bundle/ruby/2.0.0/gems/newrelic_rpm-3.6.2.96/lib/new_relic/agent/instrumentation/unicorn_instrumentation.rb:22:in block (4 levels) in  vendor/bundle/ruby/2.0.0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:500:in spawn_missing_workers vendor/bundle/ruby/2.0.0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:511:in maintain_worker_count vendor/bundle/ruby/2.0.0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:277:in join vendor/bundle/ruby/2.0.0/gems/unicorn-4.6.2/bin/unicorn_rails:209:in  vendor/bundle/ruby/2.0.0/bin/unicorn_rails:23:in load vendor/bundle/ruby/2.0.0/bin/unicorn_rails:23:in 

has seen kind of error before?

edit

i got 10th exception in prod, suggestion how should proceed?