Partial rendered with AJAX not working correctly

I render this partial with AJAX:

<% if current_user.profiles_shown_video.where("video_id = ?", params[:id]).count == 0 %>
  <p class="none"> None </p>
<% else %>
  <ul class="shown_users_list">
    <% current_u开发者_如何转开发ser.profiles_shown_video.where("video_id = ?", params[:id]).each do |p| %>  
      <li><%= link_to image_tag(p.photo.url(:thumbnail)), profile_path(p), :class => "feed_image"%> 
          <%= link_to "#{p.user.name}", profile_path(p), :class => "normal squeeze" %> 
          <%= link_to image_tag("/images/facebox/closelabel.gif"), showable_video_path(ShowableVideo.find_by_user_id_and_profile_id_and_video_id(current_user, p, @video)), :method => :delete, :remote => true, :class => "showable_video_delete" %></li>
    <% end %>
  </ul> 
<% end %>

For some reason, the first if statement is always being evaluated to true, even if it shouldn't be. In other words, <p class="none"> None </p> is always being displayed. If I refresh the page, it gets corrected. Why is the if statement of this partial not being evaluated correctly when rendered with AJAX? How can I fix this?

Here's the destroy action:

def destroy
  @showable_video = current_user.showable_videos.find(params[:id])
  @showable_video.destroy
  respond_to do |format|
     format.html {redirect_to :back}
     format.js
   end
end

This is in destroy.js.erb. It renders a partial containing the first block of code above:

$("#shown_users_div").html('<%= escape_javascript(render("showable_videos/shown_users")) %>')

ActiveRecord caches associated objects. After running @showable_video.destroy, current_user (itself probably being cached) will still have @showable_video in memory, so the collection will be non-empty. After creating, updating, or deleting the database record, you must run:

current_user.reload

so that it reloads associated objects from the database.