Button occurs only on sites, not on posts

Hello, the button does not appear on the posts (even though “post” is selected), but only on the pages (when it is selected in the button area). If it is manually inserted using a shortcode, the button does appear, but an image from a completely different post is shown for printing. However, this image is always the same, regardless of which post the shortcode is inserted into.

The page I need help with: [log in to see the link]