This bug has existed for 2 years and I’m extremely puzzled as to how it’s never been fixed.
It’s really simple: In the editor, the “Hide During Breakpoints” settings are never reflected in the live view for any sizes except full-size desktop and mobile phone. For all other sizes the Hide settings are completely ignored in the editor (they work in the actual front-end view, but that’s not helpful when editing).
I’ve attached an example with a Gap, though it applies to virtually any element.
The Gap is set to hide on desktops thru wide tablets. Yet despite viewing the page in laptop/small desktop view, and the gap is set to hide for this size, it’s there.