All I can think of is that it is rendering each screen differently when there is a rapid lateral displacement of the image. I guess one way to test would be to have stationary scenery and move your head rapidly and see if the same thing occurs.
I have a Reverb G2 V2 as well and can’t say I have ever noticed this in game, but when the DCS menu loads in VR it does ‘flicker’ with a double image until it has fully loaded. I have just lived with it.
I am not running openxr and was going to suggest maybe that is your culprit… but if you had the same issue with IL2 and Steam VR then I’m not sure?
Update: looks like there are issues with the G2 and 3090ti - RTX 3090Ti no joy with Reverb G2