The issue seems to be in the modal.js file of the ionic library

https://github.com/driftyco/ionic/blob/1.x/js/angular/service/modal.js#L194

The temporary fix:

var isInScroll = ionic.DomUtil.getParentOrSelfWithClass(e.target, 'scroll');
if (isInScroll !== null && !isInScroll) {
    e.preventDefault();
}

Another possible solution is to add the class=”scroll” to your input element that is of type range.

Link to the github issue.