Chrome made touchstart and touchmove listeners on the document and window passive by default, which improves scrolling everywhere and silently breaks anything relying on preventDefault() there.
// now a console warning, and the default is not prevented
document.addEventListener('touchmove', e => e.preventDefault());
// opt back in explicitly
document.addEventListener('touchmove', e => e.preventDefault(), { passive: false });
A pull-to-refresh suppressor or a custom drag implementation is the usual casualty, and the symptom is that it simply stops working on mobile Chrome with a warning nobody reads. The better fix in most cases is touch-action: none in CSS, which tells the browser up front rather than fighting it per event.