<p>A lot of people across the SE network have noticed the same thing: see <a href="https://meta.stackexchange.com/q/328642/225179">Massive user removal in one night?</a> &amp; <a href="https://meta.stackexchange.com/q/328672/225179">Please update the text in help for &quot;User was Removed&quot; reputation changes</a>.</p>

<p>In fine, when a user deletes their account, whether or not to reverse the votes they've cast is decided by SE staff if the vote count exceeds a certain threshold.</p>

<blockquote>
  <p>Note that we will not define the exact thresholds for how many votes will trigger review.</p>
</blockquote>

<p>Reasons for not preserving votes include, but are not limited to, vote fraud.</p>
