My Outlook for Mac is suddenly "acting" buggy. Usually, when I receive a new email, it shows up at the top of the list. Recently, this has changed..I get the chime indicating that there is new mail, but when I look, the new mail isn't there. In many cases, it actually shows up in my inbox many hours later. When it does show up, it is timestamped with a much earlier timestamp. This seems to be very ramdom, it doesn't happen with all emails.

I do keep up with updates, this is Outlook for Mac 2011, version 14.2.5

Thanks!