When I leave preview mode or view my site in a published state, the cart icon expands from 24px to 125px. I have the icon saved at 24px

Does anyone know why the editor is doing this? Or if anyone has had the same problem what the solution might be?

Does the issue exists on different devices (iPhone, android, browser on desktop etc.)? The preview mode simulates behaviour of different browsers but is not perfect.

You might wanna check the height, widths etc. of the icon, grid, section etc. Could be a rogue value in vh, % or something else.