I have weird grass/blur effect. You can see it in video.
I changed textures/normals and few other parameters(turned off motion blur) but it didn’t worked.
It’s my grass shader.
Try to increase rendering resolution.
Roughness in your material is set to 0 and your grass is extremely reflective. That artifact that you are seeing is probably result of screen space reflections, try setting the roughness to 0.5 and that should work.
It didn’t worked:/
Check AA-method in “project settings” - try to switch from “temporal AA” to another method
Ghosting from Temporal Antialiasing.
No solution do get rid of the ghosting with TAA active, you must fall back to FXAA like acron35 said.
It actually is possible to reduce the ghosting, but it also depends on the properties of the scene and the way you set everything up. FXAA can be a better fit under given circumstances, but it won’t always work on scenes where strong edges are more apparent (eg structures).
The key to reduce the ghosting is that you have to restrict the temporal buffer to lower blending, and treat the flickering edges by weighting the higher blending factors to those areas. The entire content is actually flicker a tiny bit, but you just can’t see it really since the edges are the dominant contributors when recognizing the visual information and they remain temporally stable this way.
Is this based on Disney’s new TAA?
EDIT: never mind, just looked it up. Disney’s solution is very slow.
No it is indeed Epic’s TAA i only just modified and extended it a tiny bit to get this fast output. I did also have mentioned this in the description 
Although a couple of things still can be optimized on the original taa as well, fewer sample points can make up rather similar results, which always good for the preformance, but TAA is not that expensive performance wise to dive into optimizations otherwise.
This disney model looks very impressive, thanks for bringing my attention to it! However, yes the 7msec frame time on a gtx 980 is a little hurt to consider it generally in realtime applications. It still will be useful in some cases, considering the quality is brilliant.