[CentOS] CentOS 6 : TigerVNC auto disconnect in version 1.1.0-18

Hi,
When TigerVNC was updated from version 1.1.0-16.el6 to 1.1.0-18.el6, our VNC client kept getting killed after connecting for about 180s. We had to downgrade back to -16 to avoid this issue.
We have a setup which allows users to log into our system via a web browser, with TigerVNC as the VNC server, noVNC as the client, and connecting via Websockify. With the update of TigerVNC, the VNC client kept getting killed 180s after logging in -- the user is returned to the login page. We are using CentOS 6.8.

We can't figure out what the problem might be -- the update seem to be mostly changes related to x11-server - could this be somehow related? The timing of the logout seems quite precise, as if it is triggered by some timer. Does anyone have any idea what the problem might be? 

Is this the best place to ask about this? The changes between -16 and -18 seem specific to CentOS (I can't find them on the source at TigerVNC's website), so I assume that is not the place to ask about this issue. 


Kish Shen