If it happens in Ace’s demos, it would be something to report for it along with reproduction steps.

For a workaround, you can try opening ace.js in a text/code editor, finding this bit (around line 1503 as of writing), and editing the factor to be a higher value

    if ("onmousewheel" in el) {
        exports.addListener(el, "mousewheel", function(e) {
            var factor = 8;
            if (e.wheelDeltaX !== undefined) {
                e.wheelX = -e.wheelDeltaX / factor;
                e.wheelY = -e.wheelDeltaY / factor;
            } else {
                e.wheelX = 0;
                e.wheelY = -e.wheelDelta / factor;
            }
            callback(e);
        });

(maybe also add a console.log(e.wheelDeltaX, e.wheelDeltaY, e.wheelDelta) and let me know what the values are)