Wrong structure after insert list item

[Martin]

1. Crete list like this:

<ul>
 <li>a
  <ul>
   <li>[b</li>
   <li>c]
    <ul>
     <li>d</li>
    </ul>
   </li>
  </ul>
  </li>
  <li>e</li>
  <li>f</li>
</ul>

2. Select b and c item as in example
   
3. Type some char e.g. 'a'

Expected result
New char will be replaciing 'b' item and 'c' item will be removed

Actual result
New char is replacing 'b' item (correct) but depends on browser 'c' is always incorrect

[Garry Yao]

Definitely a usability issue, but we need to understand priority properly.