There seems to be a lot confident commenters here waving this away as just a downside of FG in general. Yes FG can produce artefacts when not enough info is known, but the weird ghosting, texture juddering (especially trees) with FG in MFSD is not one of them. It was very odd, with tearing and all sorts of vomit inducing effects not seen in any other game, yes even at lower FPS.
I’ve had this since I got a 4090 but after updating to the latest NVidia driver 555.22 (and SU15 BETA) I am no longer seeing this.
Zahi, yes I too have a 2nd instance/window, although I never tried what you describe before upgrading drivers.
On another note, there is a bug in that FG does not work on a “2nd Window” added via Experimental page, I get a smooth FG enhanced display on the main window and a (half smooth) 2nd monitor!
What I’ve now realised though is you can run in Windowed mode and drag the 1 window across both monitors. Sadly you cannot use a window resize tool like SRWE as it seems they’ve masked the window/application.
Classic MSFS, so nearly the perfect experience, but always something to improve.