Hi Vagelis,
The strange layout is due to an incorrect container. From the page source I am guessing you are using Fusion builder or something similar. The plugin shortcode is placed into a Text widget, which causes the issues. The plugin source on both pages is malformed, as the text container automatically adds paragraph blocks and whitespaces (as it expects text instead of HTML).
If you change the block type in the Fusion builder from text to a shortcode or custom HTML it will very likely resolve the issue.