hi,
The short answer is, no. The "Apollo XI Field at Sepulveda Basin_PI" in my opinion is not one of the better photo fields for Rf9.x and has some inconsistencies. The "grass" is behaving as it should. The wheels should appear to sink into the grass, not ride up on the tips of the blades of grass... the problem is that some of the concrete and asphalt surfaces (not the runway) behave like the grass... the plane's wheels appear to sink into the concrete!
If you stay on the runway, you won't have any problem; I didn't when I tested.
This is because of the way the "photo field" is overlaid on the model terrain. I suppose you could create your own modification of the photo field where you place concrete pads where they belong in the photo, so that plane's wheels are riding on the pad object instead of sinking into the photo.
As far as the grass goes, this is quite normal. At my home field, most of the wheels of most of my models completely disappear in the grass! The only ones that don't are my Carbon Cub SS, and my Turbo Timber. Keep in mind that the P51D is not scale... its a model (tiny). It has very small wheels; probably smaller than the Apprentice STS.
I didn't even think that this was possible, but now I have exactly the same problem. Thanks to everyone who wrote about the solution to this problem, I finally figured it out