This doesn't only happen in VR, but also on a regular screen.
In the cockpit view, rain on the visor used to be blown sideways by the wind in F1 2016, 2017, 2018, and 2019, but I don't know why this was removed. Maybe it was because of virtual reality or a deeper change in the particle rendering system (which seems likely, since the spray is now very white and different).
It's really strange to see rain hitting the visor and just falling straight down — so unrealistic that I no longer play in the rain. It's a shame, because the car handling in wet conditions has improved a lot.
You can remove this "rain on visor" effect by disabling particles in the graphics options, but that also removes all spray behind the cars.
Please consider restoring the wind-blown visor rain effect, or at least give players an option to disable the visor effect separately from the rest of the particle system.
Thank you for your attention to detail — it’s one of the things that made the older F1 titles so immersive.