Hi Ilves.com admins and Silvi,
Your problems are not related.
MCB cannot know what blocks there are on a non-published article. I'm working on a way this might work, but didn't have time just yet. So an article has to be published before this plugin knows what blocks you want to use.
A workaround is to disable HTTP requests and and click 'Preview post' when it's not published yet. Hope this helps.
MCB uses $post (the global variable WordPress uses to define the current post) when defining what page is being viewed. However on the 'blog' page, WordPress doesn't put this blog page in $post. So MCB doesn't know that there are additional blocks on the news page.
There is a way to know, but it's not built in at the moment. It's on the list.
You can try something like this as a workaround (if the page name is "News"):
$old_post = $GLOBALS['post'];
$GLOBALS['post'] = get_page_by_title('News');
$GLOBALS['post'] = $old_post;