Masonry gap size not maintained

I have created a portfolio layout with images. When I choose the masonry layout, the gap size doesn’t seem to work.
I’ve set the gap to 0 and I expect the layout to look like this. But instead on updating or publishing, the page changes to this.

I’m using gutenberg, although this already happens in the portfolio layouts editor. Is there any solution to this problem?

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