Problem maintaining connection to real controller

I am using RobotStudio version 5.15.02 to connect to IRC5 controllers and I am having trouble maintaining my connection. By that I mean edits made on the flexpendant sometimes do not appear on the RobotStudio screen and vice-versa. To resolve the problem I need to delete the controller from my controller list and add the controller again. This generally works, but I often lose many edits in the process. I have seen this issue on many of our robots and all are running Robotware 5.15.02. Is this a known problem? Any ideas?