I set up a server with 30 AIs to run several tests this weekend.
Tried current and old video drivers, changing settings on Nvidia panel and Oculus and never managed to finish a race without the issue occurring.
The only thing that changed this and allowed me to finish a race without the problem occurring was using the OpenOVR plugin, which allows me to use rFactor 2 without SteamVR.
https://gitlab.com/znixian/OpenOVR/blob/master/README.md
The only problem I found using this plugin is that the rF2 crashes when the server calls Next Race.
In internet research I found several reports of people who have this type of freeze in other games, using the Rift, an Nvidia 1000 series card and SteamVR. I believe it is an incompatibility of this scenario.
I don't know how difficult this is, but if the rF2 could have this type of plugin developed by Studio 397, it would be of great value to the VR community, because besides avoiding problems with SteamVR, the performance is better.