Hovering preciseness in Chrome

Elements with no height but subpixel offset can be hovered in Chrome, but not Firefox. Bug? Not in spec?

by Just a Student

HTML

<ul class="ignorant">
  <li>I am ignorant of your pointer. If you see me, something went wrong!</li>
</ul>
<ul>
  <li>I am not. Hover me!</li>
</ul>
<ul class="ignorant offset">
  <li>I should be ignorant of your pointer. If you see me, something went wrong!</li>
</ul>

CSS

ul {
  max-height: 0;
  overflow: hidden;
  margin: 10px;
  padding: 0;
  border: 10px solid #bada55;
  list-style-type: none;
  transition: border-color .4s;
}
ul:hover {
  max-height: 100px;
  border-color: #de2d26;
}

ul > li {
  padding: 10px;
  pointer-events: auto;
}

.ignorant {
  pointer-events: none;
}

.offset {
  position: relative;
}