Featured image: bug page builder

Hi all,
I’m new on the forum, I hope that’s the good way to start my topic.
I’m using Sahifa, a Tielabs theme. All is going right expect a little option I can’t configure.
It’s all about featured image.

The page builder of my theme allows me to have featured image on my post, which is good.
The bad side is that I can’t have a featured image on my page…If I add one, the page builder gets broken and so my page is down. The featured image is not even visible if I do that. If I add the image and actualize on the page builder, the page is ok, but the featured image doesn’t show as well.

Do you have any ideas how can I fix it ?

Thanks a lot,
Simon