Wrong mime type in rjs response in Rails 2.2.2 (sometimes)

rjs templates in Rails 2.2.2 sometimes set the mime type of the response to text/html instead of text/javascript. Therefore no js interpreted in the browser. Rails 2.2.0 works correctly; 2.2.2 does not appear to.

Failure Example: http://www.noexpectations.com.au Scroll to the bottom of the page to cause a js request to the server which returns javascript from an rjs template. Header mime type is incorrectly set as text/html.

It does not happen in all cases. For example, http://www.noexpectations.com.au... has the same "endless page" functionality and in this case the rjs response has the correct mime type of text/javascript

Failing rjs template in 2.2.2 (works in 2.2.0): page.insert_html :bottom, :articles, :partial => "articles" if @articles.page_count > @articles.page page[:loading].hide page.call 'checkScroll' else page[:loading].hide end

Note partial :articles calls other .html.erb templates possibly causing response mime type to be overwritten (?):

<% for article in @articles -%>

<div id="<%= 'article_' + article.id.to_s -%>" class="_article" >
  <h2><%= link_to h(article.title), article %></h2>
  <%= render :partial => "article_byline", :locals => {:article => article} -%>
  <%= render_excerpt(article) -%>
  <%= render(:partial => "article_footer", :locals => {:article => article}) -%>
</div>

<% end %>