Sometimes it works, other times it shows the site logo

Hello, I’m seeing some weird behavior. On some posts, for example on this one: https://plup.co/este-video-nos-ensena-que-lo-que-sentimos-debemos-decirlo-ahora-mismo/

the featured image appears fine.

However on other posts, for example on this one: https://plup.co/que-harias-tu-si-estuvieses-en-esta-habitacion/

the featured image is not chosen, the site logo is chosen as the thumbnail by facebook.

Why us this?

Thanks

https://www.ads-software.com/plugins/facebook-featured-image-and-open-graph-meta-tags/