PrettyFaces - wrong parameters via f:params tag - url-parameters

Question

I can't figure out why the below code in the view:
<ui:repeat value="#{postsController.posts}" var="post">
<tr>
<td>#{post.title}</td>
<td>
<pretty:link mappingId="comments">
<f:param value="#{post.id}"/>
Comments
</pretty:link>
</td>
<td>
<pretty:link mappingId="edit">
<f:param value="#{post.id}"/>
Edit
</pretty:link>
</td>
<td>Delete</td>
</tr>
</ui:repeat>
and this one in the bean:
#Component
#ManagedBean
#RequestScoped
#URLMappings(mappings = {
#URLMapping(id = "posts", pattern = "/posts/", viewId = "/faces/posts/list.xhtml"),
#URLMapping(id = "edit", pattern = "/posts/#{postsController.id}/edit", viewId = "/faces/posts/edit.xhtml"),
#URLMapping(id = "new", pattern = "/posts/new", viewId = "/faces/posts/new.xhtml")
})
public class PostsController {
#Autowired
private PostService postService;
private List<Post> posts;
private Post post = new Post();
private Long id;
public List<Post> getPosts() {
return postService.findAll();
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public Post getPost() {
if(!post.isNew()) {
this.post = postService.findById(id);
}
System.out.println("++++++++++++++ getPost: " + post);
return post;
}
public void setPost(Post post) {
System.out.println("++++++++++++++setPost: " + post);
this.post = post;
}
public String create(final Post post) {
postService.save(post);
return "pretty:posts";
}
public String update(final Post post) {
System.out.println("++++++++++ update post: " + post);
postService.save(post);
return "pretty:posts";
}
}
The edit page:
<h:form>
<div class="row">
<div class="small-3 columns">
<label for="right-label" class="right inline">Title</label>
</div>
<div class="small-9 columns">
<h:inputText value="#{postsController.post.title}" required="true"/>
<p>
<h:commandButton value="Update" type="submit"
action="#{postsController.update(postsController.post)}"
styleClass="button radius"/>
</p>
</div>
</div>
</h:form>
give the wrong behaviour as follows:
when I edit an existing post, there is no title displayed in the texfield on the edit page, as if there is no ID passed from the parameters. However teh URL is correct: posts/1/edit.
after creating a new Post and hitting the edit link, the title of the Post is displayed correctly.
when I create another new Post, the title textfield id filled with one of the last Post.
update method, even it is called, keeps the original title value and never updates the existing Post.
What am I doing wrong here?
Thannk you.