I did some more testing locally with fast moving emitters, analyzing the substepping interpolation frame by frame.
In the case of unlimited FPS (~200 FPS range in case), I did see substepping interpolation that could be made smoother. We will work on improved interpolation for case.
You can verify if is the by setting t.MaxFPS to align with the simulation rate.
did not manifest in previous VR work, where simulation rate was aligned to FPS.