Missing Required contact details

Don't know how it happened. Only about 38 times.

SELECT top 1000 t.*
FROM dbo.Transactions t
WHERE  TransactionId is null and NOT EXISTS (
    SELECT 1
    FROM dbo.TransactionAnswers ta
    WHERE ta.TransactionId = t.Id
      AND ta.QuestionSetId = 1
      AND ta.QuestionId = 9
);

Possibly could have a server side check. (9 is the email)