OK, right.
First up, Outlook. It doesn't cope all that well with IMAP. I had the same dates problem, if you download the latest patch, it should (according to Microsoft) fix it. That seems to work OK, but still leaves a few IMAP related bugs. (I've now moved over to Netscape Mail after far too many sleepless nights).
On the second question however, I'm not certain, but have seen something like it before. It happened to me (albeit only on 4 messages) and the cause was one message which was very large (20MB), the server was getting so far, then just dropping it, and starting again, each time getting as far as the 20MB message then dying.
Hope that may help!
Matt