Grey Space Appearing On Some Browsers & Not On Others

I've produced a site, which is basic but displays correctly to me. However my client and his management gets various iterations of the site displaying incorrectly, a recurrent one is grey line appearing at the bottom of the site. Attached images. @Ziggy has been really helpful here, and explained that the situation is that i'd not set a row count big enough and so on some browsers this could display incorrectly. However, i keep increasing the row count and it still appears with the grey line. I've taken it up to 34 so far, but this obviously effects how the site looks.

I've asked Support and they suggested adding a section at the bottom of the page. But that just means that it looks like there is a huge footer, and looks terrible.

I'm sure it's something simple, but i can't work it out.
Is there any reason why a site that has a row count of 28 (no gap) would be displayed incorrectly? Any help is going to be hugely appreciated.

I've used this custom code for a font incase that could be an issue.

//---Custom Fonts---//
@font-face {
  font-family: 'aldine-401-italic-bt';
  src: url('https://static1.squarespace.com/static/63a0d5c0d3b7cc5b3a17657a/t/63a0d686f6cd273e254d4027/1671485062982/aldine-401-italic-bt.ttf');
}
h1, h2, h3, h4, h5, p {
  font-family: aldine-401-italic-bt;
}
header#header *, footer.sections * {
  font-family: aldine-401-italic-bt;
}

What is your site url? We can check easier

Yooo sorry for slow reply. check https://www.anderttysma.com/

Thanks so much