When incorrect, is it by when it's received by the device or by when it's processed by the BES? I believe it's the latter, but I may be mistaken. Many desktop clients exhibit this same behavior, including Exchange/Outlook. When having mail server or client issues, it's not beyond the scope of imagination for you to receive messages with two different time stamps (one in the header and one in the message list). I would almost guarantee that you can find a coinciding log entry with the two different time stamps on the BES (I can't remember the exact line entry, but it actually references what the current time is (time processed) and when the message was actually received).
In the beginning the Universe was created. This has made a lot of people very angry and is widely regarded as a bad move.