Summary Block Breaks Page With 15+ Posts - Can This Be Fixed With CSS?

A client of mine recently asked me if I could increase the summary blocks on pages to have the maximum amount of posts possible (30 is the limit if I'm not mistaken). This is a site for a classical music agency and PR is a very important part of it, so they want to display as many news stories (created as blog posts) for each musician as is possible. However I noticed that when you have 15 or more posts on display, such as can be seen on this page here (https://schwalbeandpartners.com/laurence-cummings-conductor), it breaks the page width (at least on small desktop screens). You can see the effect by scrolling to all the way to the right, and there is now some blank space there. 

Compare that to another page with 14 or less posts, such as this one: https://schwalbeandpartners.com/kathryn-mueller-soprano 

That one has no extra white space on the right side. I've seen other folks post about this and I've been driving myself a bit crazy trying to find the answer - haven't seen any good responses yet that actually solve this. I even tried putting spacer blocks on either side of the summary block so it doesn't take up the full page width, and it STILL has white space on the side!! Really bizarre that Squarespace haven't figured this out yet. Anyone have any ideas?? 

Thanks in advance. Please let me know if you need additional clarification. 

I am unable to reproduce the issue you describe.

I tried on Chrome mobile emulation and an iPhone.

@creedon As far as I can tell this is a desktop-only issue. I'm viewing it on a 2021 Macbook Air 

1 hour ago, NickHart said:

As far as I can tell this is a desktop-only issue.

I went to mobile sized devices as you mentioned a small screen in your original post.

I originally loaded on desktop and I saw no issue there as well.

Are you viewing with Safari?

16 hours ago, creedon said:

I went to mobile sized devices as you mentioned a small screen in your original post.

I originally loaded on desktop and I saw no issue there as well.

Are you viewing with Safari?

@creedon Never mentioned mobile devices, although I suppose I should have specified desktop (I previously said "smaller screens" so I see where the confusion came from). The original post has now been edited to clarify. 

I am viewing this page (https://schwalbeandpartners.com/laurence-cummings-conductor) on both Chrome and Safari on a Macbook and it's pretty noticeable in both browsers - in fact Safari is even worse. I've attached two screenshots to show the white gap that appears on the right side of the page, first screenshot is Chrome and second screenshot is Safari. 

Ah ha! I'm now seeing the issue. I don't have a solution but an observation. The issue seems to be between 768px and 1480px viewport width sizes.

@creedon Exactly. Any ideas here? As I said, even trying to put spacers on either side of the summary block still causes the page-breaking issue in that pixel range. I saw other posts suggesting a min and/or max-width but that hasn't seemed to help..