Perhaps I was a bit flippant/expedient in my last post, so for giggles here's the frame I posted from Sovapid's YT video and see what it might reveal:
What it shows to me is that there are issues with the lighting, shading and rendering part of the engine:
1. The underlying terrain and shading thereof looks fine, but a little hard to tell as the shadows cast by the "normal" rock objects are short, but that looks OK.
2. The big nasty chevron of shadow across the landscape at the 1-2 o'clock position looks like a bugged shadow cast from whatever is up in the sky shooting at the buggy - it lacks shape definition and has no edge blur. It also looks like it might be in the wrong position if the ship casting it is behind our view. So I can only assume this is a separate shading pass from the terrain shading pass and poor framerate/network position updates might account for it, or could be the cause of poor frame rate/stutters.
3. Interestingly the near terrain with the "detailed" texture looks like it has been applied to the underlying terrain after the shadow pass, which is why it occludes (takes a lump out of) the shadow that I'm assuming is cast by the ship flying overhead. That detailed terrain texture also appears to be the source of tesselation (think of it in this case as extreme bump mapping, but its actual geometry generated after the texture is applied). IIRC CryEngine introduced this in 2013/14 and you can set the amount of geometry (bumpiness) generated from an attribute(s) in the texture.
4. If the overhead ship is another player then it could be that the shading passes and order of texturing and rendering have got out of order with positional updates (networking again), with potentially other issues if that's not the case.
Anyway you cut it you have rendering/lighting/shading bugs in the engine, which at best look a bit nasty and at worst might be causing crashes, memory leaks and other weirdness. I've seen these kinds of issues fixed with (the correct) 6 lines of code, but have also seen the render engine having to be dismantled and almost re-written to fix. Luckily it's still Alpha.
To be fair I would also expect Frontier to be tackling this kind of thing in their upcoming new lighting model as well, but I'd hope it never reaches the public gaze...