iOS css -webkit-transform: scale doesn't offset touch events

help you fix your problem I'm facing the same problem: I want to scale an element on hover, and when doing so every text on the page flickers. I'm also on latest Chrome (21.0.1180.89) and OSX Mountain Lion.
Actually, adding

-webkit-backface-visibility: hidden;
-moz-backface-visibility:    hidden;
-ms-backface-visibility:     hidden;

wish of those help Due to my small amount of experience with JavaScript I didn't realise that the callback could in fact modify the position, even though it doesn't return anything. This is because in JS apparently parameters are by default passed by reference.
Here's a working code:

// Couldn't figure out a way to use the coordinates
// that jQuery also stores, so let's record our own.
var click = {
    x: 0,
    y: 0
};

$('.draggable').draggable({

    start: function(event) {
        click.x = event.clientX;
        click.y = event.clientY;
    },

    drag: function(event, ui) {

        // This is the parameter for scale()
        var zoom = 1.5;

        var original = ui.originalPosition;

        // jQuery will simply use the same object we alter here
        ui.position = {
            left: (event.clientX - click.x + original.left) / zoom,
            top:  (event.clientY - click.y + original.top ) / zoom
        };

    }

});

it helps some times Here's the result of my extensive investigation before I gave up.
There are two major problems involved in applying transform: scale to content inside iframes on iOS. The first was what I pointed out in the original question, that content starts to drift away from it's specified location on the page if you are using fixed position elements. It works up to a point that seems to be based on the original size of the element, the scale factor, and presumably the viewport width. In my tests a large element might scale and position perfectly when scaled at any factor greater than 0.85. A small element might be positioned perfectly so long as the scale factor is at least >3.5. It seems almost random, so I didn't bother determining what the exact point was.

container.css('top', (document.body.scrollTop + window.innerHeight - container.height()) + 'px');
container.css('left', document.body.scrollLeft);

may help you . Somehow I got this fixed, and I have no idea how. -webkit- will always remain a mystery...

around this issue You need to break up the adding the div and adding a class to it, e.g. using a setTimeout().
W/o the above, the animation won't apply the transition, as it does all in one go.

$("button").click(event => {
    
    let div = $("<div></div>");
    div.insertAfter("button");
    setTimeout(function() {
      div.addClass("animate");
    }, 10)
});

div{
  height: 50px;
  width: 50px;
  background: #000;
  transform: scale(0);
  transition: transform 1s;
}

.animate{
  transform: scale(1);
}

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<button>Button</button>

$("button").click(event => {
    
    let div = $("<div></div>");
    div.insertAfter("button");
    div.addClass("animate");
});

div{
  height: 50px;
  width: 50px;
  background: #000;
  transform: scale(0);
}

.animate{
  animation: scale 1s forwards;
}

@keyframes scale {
  from { transform: scale(0); }
  to   { transform: scale(1); }
}

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<button>Button</button>