just tested on macOS in Firefox, Chrome and Safari: got horizontal scrolling. On iOS in Chrome and Safari there is no scroll but a white line on the right. Of course it doesn’t reveal because macOS like to hide scrollbars but if I try to scroll right, there is a little scrollable space. You can try this
document.getElementsByClassName("gutter-condensed gutter-lg flex-column flex-md-row d-flex")[0].clientWidth
document.getElementsByClassName("gutter-condensed gutter-lg flex-column flex-md-row d-flex")[0].style.width = '100%'
document.getElementsByClassName("gutter-condensed gutter-lg flex-column flex-md-row d-flex")[0].clientWidth
edit: add code to spot the bug