Based on the information I see using this Facebook’s tool,
https://developers.facebook.com/tools/debug/
your post is telling Facebook that the cover image should be your site logo (see next to “og:image”).

You may want to try disabling plugins or switching to a default theme, running your post through the above tool (make sure to hit the “Scrape Again” button), and see if the issue goes away. It’s likely one of the plugins or your current theme is preventing from the featured image to be set as the og:image.