Hi there!
You'll be happy to know this isn't a bug
What you're seeing is the result of an admin-configurable feature known as "Inactivity Timer", and that its working as intended.
Each port has a parameter known as "Inactivity Timer" which has a valid range of 0-3600 seconds (100 seconds being the default). With the default setting, if there is no activity over the port for 100 seconds, the port will close. And yes, closing the port will have the effect of dropping your connection.
This feature is in place to ensure that improperly closed connections to the ports of the CM do not stay open indefinitely, thereby preventing other users from being able to access it. We feel this is a very beneficial feature!
If you would like to disable this feature, an administrator can go into the port settings and set the Inactivity Timer to 0 (disable).
Mike