A bug has been discovered when using Windows Phone 7.5 Mango with an old Exchange 2003 account that could be damaging in the workplace when trying to keep track of a conversation. When you reply to an email, normally the text of the original email is included at the bottom, and you’ll see it at the bottom of your email reply on Windows Phone 7.5. The problem is that when you send it through an Exchange 2003 account, the entire text from the previous message is removed leaving only the header information of the previous message. This can cause some confusion especially if your message is refering to something in the quoted messages in the thread.

There are a couple of work arounds though. If your intention was to send the conversation to some one else, “Forwarding” the email will still work and will include the conversation as an attachment. The other work around is to copy/paste the previous message’s content into the body of the reply. Hopefully Microsoft can issue a fix for this problem either on the Exchange 2003 Server end or on Windows Phone 7.5′s end since the bug is certainly a bit embarassing. Ideally they would fix the bugs with reply/forward status information being communicated to IMAP & Exchange 2003 servers, too, but I’ve been wishing for that since the 20th century.

Source: Windows Phone User Voice via Engadget