We are using 2.14 Pro and some of our users have experienced the same behaviour. The browsers used are IE and FireFox on Windows, and FireFox on Linux and Solaris platforms.
Also it seems intermittent as explorart said, it may not work for a short period of time and suddenly there is no problems and everything is working fine! Strange. Can this have something to do with the capacity of the connection in some way? Or the configuration of the browser?