Header is separated from thumbnails

Great plugin!

The heading “RELATED PRODUCTS” is not always connected to the thumbnails below the header. It seems to be separated by the short product description.

Nevertheless in a few cases it seems to work, e.g.:
https://www.thecavemangrill.nl/en/product/classic-grill-outdoor-terrace-garden-barbecue-wood-fire/

It has nothing to do with the number of images in the product gallery.
Is there a way, maybe with CSS to keep the header and thumbnails connected?

Thank you so much!

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