rails log:

Completed 500 Internal Server Error in 147ms (ActiveRecord: 7.2ms)

ActionView::Template::Error ("\xD0" from ASCII-8BIT to UTF-8):
     8:   initFilters();
     9:   <% query.filters.each do |field, options| %>
    10:    
    11:    addFilter("<%= field %>", <%= raw_json query.operator_for(field) %>, <%= raw_json query.values_for(field) %>);
    12:   <% end %>
    13: });
    14: <% end %>
  app/helpers/application_helper.rb:1076:in `raw_json'
  app/views/queries/_filters.html.erb:11:in `block (2 levels) in _app_views_queries__filters_html_erb___3298721160672590463_41811000'
  app/views/queries/_filters.html.erb:9:in `each'
  app/views/queries/_filters.html.erb:9:in `block in _app_views_queries__filters_html_erb___3298721160672590463_41811000'
  app/views/queries/_filters.html.erb:1:in `_app_views_queries__filters_html_erb___3298721160672590463_41811000'
  app/views/issues/index.html.erb:19:in `block in _app_views_issues_index_html_erb__1236953358055814698_39181580'
  app/views/issues/index.html.erb:11:in `_app_views_issues_index_html_erb__1236953358055814698_39181580'
  app/controllers/issues_controller.rb:77:in `block (2 levels) in index'
  app/controllers/issues_controller.rb:76:in `index'