Featured Image displays in blog posts

Hi, For some reason when i create a blog post (which contains an image by clicking the ‘add media’ button) and add a ‘Featured Image’ to display on blog feed page, the featured image is also displaying in the actual post, resulting in duplicate images in the published post. How to stop that?
Here is the blog feed url: https://www.artbyanthea.co.nz/blog/
Here is the blog post url:https://www.artbyanthea.co.nz/new-patchwork-series/

Thank you for your help.