I don't know if this is an issue with React or IE11 but when an the input initially contains an EN-dash (8211) it fires the change event. 
JSFiddle http://jsfiddle.net/uH539/10/

if (style1 == null || style2 == null) {
    return;
  }
  if (shallowEqual(style1, style2)) {
    return;
  }
  var componentName = component._tag;
  var owner = component._currentElement._owner;
  var ownerName;
  if (owner) {
    ownerName = owner.getName();
  }
  var hash = ownerName + '|' + componentName;
  if (styleMutationWarning.hasOwnProperty(hash)) {
    return;
  }
  styleMutationWarning[hash] = true;
  warning(
    false,
    '`%s` was passed a style object that has previously been mutated. ' +
    'Mutating `style` is deprecated. Consider cloning it beforehand. Check ' +
    'the `render` %s. Previous style: %s. Mutated style: %s.',
    componentName,
    owner ? 'of `' + ownerName + '`' : 'using <' + componentName + '>',
    friendlyStringify(style1),
    friendlyStringify(style2)
  );