I seem to always run into obscure problems. I must be a magent for them.
The other day, my wife put a bunch of notes in an Outlook/Exchange appointment, including the address of where I needed to go to meet her. I was quite shocked when I got in my car, fired up the GPS, looked at the appointment details in my Exchange-synched WM6 phone and no notes were to be found! I had to quickly call my wife to get the address so I wouldn't be late. Thankfully, she had it on-hand.
So what would cause this? The appointment synched, but the notes were missing.
I did a little googling and found out the reason. It turns out there's a registry setting which limits the size of attached notes so you don't over-run the poor Windows Mobile device's internal storage with a bunch of crap you don't necessarily need on the go. The registry key is HKEY_CURRENT_USER\Software\Microsoft\ActiveSync\BodyTruncation. My BodyTruncation value was set to zero! From what I read, the default value should be 5000, which means it will sync up to 5000 bytes of notes. I have no idea how or when it got set to zero (maybe it was always that way), but that certainly explains why I had NO notes attached at all! :-)
I followed the advise at the above link and set the value to 20480 (hex 5000). I think 20K should be sufficient for appointment notes. But you can set it to whatever value you want!