No but has happened here as well when I try to fly VR in DCS. When I start the Reverb BEFORE launching WMR there is a good chance that it fails to start its 90FPS setup and starts in 45FPS. I guess that’s what you see in MSFS then. If I start WMR and wait until it tells me to connect a headset and THEN start the Reverb with the button on the cable it starts correctly every time.
This has happened for several weeks now and I assume it came with a Windows update.