Mobile Gallery bug on SS 7.1 with fluid editor

Site URL: https://seal-potato-w634.squarespace.com/felton-table

Hi team, 

I'm just tailoring all of the pages on my clients new website to suit mobile. On that note - isn't the way that SS populates mobile pages on 7.1 with fluid editor just totally ridiculous? There is no logic what so ever as to how they position the blocks and you end up having to redesign every page for mobile - what a nightmare and a double up. I love it that we can now easily change the layout for mobile but having to rebuild from scratch as all the blocks are in a weird order is taking way more time. 

Anyway, I am experiencing what I can only think is a bug on some of my product pages on mobile. 

You'll see with the screen shot that the pages have a large top image and then below them a Gallery of smaller images. The Gallery is a grid with lightbox so they pop out. Below this is a text box with the description for the product. It looks great on Desktop but I am having issues on mobile. 

On the editor view, the images in the Gallery are really big, with two per row. When you view on the actual website on your mobile, they're small images below the top image which looks great. The issue is, that if I make it look like the page content is properly spaced on the editor, it adds a huge space on the live page. To ensure that there isn't a huge space below the gallery, I have to place the text over the gallery itself on editor. This is really hard to guess where it should be and also such bad practice. Has anyone else experienced this before? Am I doing something stupid? Is there a way to make the editor screen and actual site look the same so it's easier to edit?

This is the product I'm currently editing - https://seal-potato-w634.squarespace.com/felton-table - password is TEST. 

Take a look on mobile. You'll see that the description is nice and close to the small gallery. But to make it look like that, the editor looks like the attached image with the text over the gallery. If I move the text below the gallery on editor, it leaves a huge white space (the length of the gallery in editor) on the live site which looks terrible. 

I hope that what I'm saying makes sense! I'll be feeding it back to SS. 

Thanks!