UE4.27 nDisplay launching casues SteamVR to crash

I have used a VRPN server and VRPN livelink to setup my inner frustum on the new nDisplay template. I have correct tracking in the editor and everything works smoothly. In the preview versions I could launch nDisplay and my frustum tracked perfectly and everything was good. But now in the full release of 4.27.0 every time I launch nDisplay with the same project files and configuration and trackers working in the editor, steamVR crashes at the loading of nDisplay from switchboard. Restarting SteamVR and getting my trackers loaded again while nDisplay is still open only causes SteamVR to crash once it has fully loaded again.
SteamVR version is 1.19.7 Beta, and have tried with 1.19.7 standard, both crash on every nDisplay launch.

Has anyone else experienceed this and if so found a solution?