I am having a similar problem with the received date showing up as "None".
We use an IMAP server and this problem is only showing up for one of our
users as far as I know. This makes it difficult for him to keep up with his
emails because he receives nearly 100 per day. He was using POP before and
never had a problem. I don't know if it is an IMAP/Outlook problem or the
fact that he has several thousand emails stored in various folders in his
IMAP account. Either way I am needing help finding a solution.