title: MongoDB C# Driver - CountDocuments erronously returns wrong value
body: <p>Ok, so this is a bit tricky.</p>
  
  <p>I have this block</p>
  
  <pre class="lang-cs prettyprint-override"><code>        var collResult = _coll.Find(cnFilter &amp; statusFilter &amp; startFilter &amp; endFilter &amp; textFilter);
          var findTask = Task.Factory.StartNew(() =&gt; {
              return collResult.SortByDescending(i =&gt; i.dim_InvoiceDate_key).Skip(skip).Limit(take);
          });
          var countTask = Task.Factory.StartNew(() =&gt; {
              return collResult.CountDocuments();
          });
          await Task.WhenAll(findTask, countTask);
  </code></pre>
  
  <p>the CountDocuments most of the time returns an accurate number representing the filtered query without Skip and Limit. But occasionally, when it has to count in excess of 25k or so, it returns the same count as the findTask result contains. (50 in most cases)</p>
  
  <p>Trying to use the old _coll.Count() and I get obsolete errors thrown at me, is there anything I can do for this?</p>