Not sure but I have been having this issue since day 1 with the Dinc. I just went into Menu>Accounts & Sync> and clicked on Facebook for HTC Sense and then removed the account. I then added the account back in, manually synced it again, then went into my address book and moved that little icon over the Web (or world Icon) and chose Facebook and then hit the menu button and had it re-sync all those contacts and now they are all properly up to date! Finally. Now I just hope it updates them manually instead of me having to do this every now and again.