Weird template behaviour

I have searched for this problem, but I can't find anything. It is a
bit frustrating

I have upgraded my application to Rails 2.0
I wish to use the new template system, so I move index.rhtml to
index.html.erb, and _feed.rxml to index.atom.builder
Delete respond_to in the action. Restart the server.

When requesting controller/index I get the right output. But
requesting controller/index.atom gets just the index.html.erb
template, without layout.

I restart the server. This time, I request controller/index.atom
first. I get the index.atom.builder template literal, without
processing. Just xml.* statements. Next, I request controller/index. I
get the same index.atom.builder literal template, this time inside the
application.html.erb layout

Any ideas?? Is it a bug?