I setup a internal test network at our company with a Windows 2012 R2 server as AD, and a Windows 10 machine. When we try to Remote Control one of these 2 systems the Latency will be around 30ms but when we try to controlling the computer it shoots ups to 12k+ ms and a few seconds later the Remote Control will crash. VNC connection works on the Server stably but when we attempt it on the Windows 10 machine it comes back with a failed to connect to the KServer error.
The kicker is that running VNC or a standard Remote Control session on any other computer at any of the companies we look over works perfectly fine, no connection or lag issues, only on an internal test network.
I'm an enterprise IT manager and, as such, all of my machines are on internal networks. I have Win 2012 AD servers and am able to remote control my Win 10 machines without issue so not sure what's going on with your setup. My VSA is Version 8 - not sure what yours is. There's not many things I hate more than suggesting you spend your valuable time waiting for support but this may be a time you need to contact support.