cached votes not updating with validates_presence_of in model

Question

I have acts_as_taggable installed and working for my products with cached votes.

After I tried to finish my validations inside the Product model with validates_presence_of the cached votes are not getting updated anymore.

Anyone had the same problem? Any hint is appreciated.

Basic validation inside the product model. If this line is not there, the cached_votes work:

validates_presence_of :original_url, :format => URI::regexp(%w(http https))

How I trigger the votes:

<% if user_signed_in? %> 
  <% if current_user.liked? likeable %>
    <%= form_tag unlike_path(likeable_type: likeable.class.to_s, likeable_id: likeable.id), method: :post, remote: true do %>
      <% button_tag class: 'btn btn-block liked' do %>
        <%= fa_icon 'heart-o' %> unlike
      <% end %>
    <% end %>
  <% else %>
    <%= form_tag like_path(likeable_type: likeable.class.to_s, likeable_id: likeable.id), remote: true do %>
      <% button_tag class: 'btn btn-block' do %>
        <%= fa_icon 'heart' %> like
      <% end %>
    <% end %>
  <% end %>
<% else %>
  <%= link_to new_user_registration_path do %>
    <% button_tag class: 'btn btn-block' do %>
        <%= fa_icon 'heart' %> like
        <% end %>
  <% end %>
<% end %>