Safari flexbox text wrapping issue

Question

I've discovered an issue with Safari (OS X): https://codepen.io/alexlouden/pen/jONyZKb

document
  .querySelectorAll('.parent')
  .forEach(el => {
    el.addEventListener("mouseover", event => {
      event.target.style.color = 'blue';
    })
  })

* {
  box-sizing: border-box;
}
.parent {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 280px;
  padding: 32px;
  background-color: #e99;
  margin: 32px;
  text-align: center;
}
.child {
  flex: 1;
  max-width: 100%;
  background-color: #99e;
}
.grandchild {
  overflow-wrap: break-word;
  border: 1px dotted black;
}

<div>
  In Safari, when you hover on the red area the XXXs will stop wrapping. <br/>
  Hover over the blue area and it will fix and re-wrap.
</div>

<div class="parent">
  <div class="child">
    <div class="grandchild">
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    </div>
  </div>
</div>
<div class="parent">
  <div class="child">
    <div class="grandchild">
Centered
    </div>
  </div>
</div>

The grandchild seems to not be respecting the max-width constraint of the child, but only when the style of the parent is modified - not when it's first loaded.

I'm wondering what's causing this behaviour, and whether this is already a known issue with Safari or if I should report the bug?

Answer 1

I guess answer is much simpler then I thought ':D !!

Just change the following css and it should work B)

.parent {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 280px;
  padding: 32px;
  background-color: #e99;
  margin: 32px;
  text-align: center;
  overflow-wrap: break-word;
}