Paddy Keaney If you have a 4k tv I have seen this happen. You may need to log into windows as an admin and set the secondary monitor to 1920x1080 and set the dpi to 100% not 150% as it may be. If this is not the issue you may just need to "lock the spotlight" on the room. I am also using the PTZ2.
Looks like the latest build 4.0.27.0 is supporting 1803. In fact when I updated my install media (instructions found https://docs.microsoft.com/en-us/SkypeForBusiness/deploy/deploy-clients/console) it required the 1803 release and wouldn't let me use 1709 saying the script (CreateSRSMedia.ps1) will not support the current build of windows and I needed at least 17134 also known as 1803.
A word of advice for anyone using the CreateSRSMedia.ps1 script. Pre-download all the files you need and put them in the folder with the script. The script was timing out downloading the Surface files directly from the CDN. Also during the mount-windowsimage sequence once the status bar at the top goes away for each step I had to press ctrl+c to move to the next line. Otherwise it just sits there for hours seeming to be hung when it has indeed completed the previous step. The script is a good script it just needs some better QA to find the bugs.