I have now had this problem on a couple of machines.
Windows 7 , office 2010. I have synced some network folders. The problem is when connected to the network I connect to a file (excel) and it appears to be online. However when I make a change and save the network version does not get updated until I manually sync the file.
This is causing many problems as some of these files are shared by many so if my changes don't go through people can then be viewing out of date data.
It does seem to be more with Excel but more testing needed.