title: Invalid formula - Operator "+" doesn't support TEXT + NUMBER. Operator "+" supports NUMBER + NUMBER
body: <p>This was working last week but now it has an error like this:</p>
  <blockquote>
  <p>Invalid formula - Operator &quot;+&quot; doesn't support TEXT + NUMBER. Operator &quot;+&quot; supports NUMBER + NUMBER</p>
  </blockquote>
  <p>Current formula:</p>
  <pre><code>COUNT_DISTINCT(CASE
      WHEN First Duration+Second Duration&lt;=24 THEN New ID
      ELSE NULL
    END ) / COUNT_DISTINCT(CASE
      WHEN First Duration IS NULL THEN NULL
      WHEN Second Duration IS NULL THEN NULL
      ELSE New ID
    END )
  </code></pre>