Custom code glitchy on display

Hi, recently I've been working on a website for an art collector and have run in to a couple issues with my custom CSS. Since yesterday evening, the homepage of the website has display errors (grid gallery images all over the place and in different sizes) which automatically resolve once I click on "Edit“ for each section (without changing anything). I've tried removing all my custom CSS and the problem persists so I'm wondering whether that could be due to code blocks.

If anyone's been through this before, please do help me figure out a solution.

Below are two screenshots of 1.the display error & 2.the way it's should be showing up.

Many thanks !

Hi. Can you share link to your site? We can help easier