Prebuilt layouts doesn’t replace the current page layout

Hi, I installed Page Builder by SiteOrigin and I find it very useful and excellent plugin.
But I have a problem with Prebuilt layouts. I made a page and used one of the Prebuilt layouts, I chose Insert and Replace current. But the Prebuilt layout didn’t actually replace the default look of the page but went over it. Can you help me fix this issue? I could show a printscreen of that problem but I didn’t find an option to attach images. Thanks!