getLastPost in Thread.pm should not cast its data, but allow the asset to determine its own type.

docs/changelog/7.x.x.txt

@@ -1,6 +1,7 @@
 7.10.27
  - fixed #12379: userImport documentation error
  - fixed #12382: WebGUI::Crud does not work with all form types
+ - fixed: Threads with no posts return the wrong lastReply data.
 
 7.10.26
  - fixed: Template diagnostics when called without a session asset.

lib/WebGUI/Asset/Post/Thread.pm

@@ -450,7 +450,7 @@ sub getLastPost {
 	my $lastPostId = $self->get("lastPostId");
 	my $lastPost;
 	if ($lastPostId) {
-		$lastPost = WebGUI::Asset::Post->new($self->session, $lastPostId);
+        $lastPost = WebGUI::Asset->newByDynamicClass($self->session, $lastPostId);
 	}
 	return $lastPost if (defined $lastPost);
 	return $self;