The conditions for when to insert <span class="name-variation"> and when to insert the corresponding </span> are out of sync. This may cause a </span> closing tag to be created, which then prematurely terminates a different <span>.

E.g. on http://bitmap.mbsandbox.org/artist/7e84f845-ac16-41fe-9ff8-df12eb32af55/relationships, the second relationship should be all yellow (including the "(background vocals)" part) because of pending edits, but isn't. This is the HTML:

<span class="mp">
  <a href="http://bitmap.mbsandbox.org/artist/2ef51c46-f2f8-4a88-bc5e-6236bac9e1c3" title="Marianne &amp; Michael">
    <bdi>
      Marianne &amp; Michael
    </bdi>
  </a>
</span> <!-- spurious -->
  (background vocals)
</span>