This is "YesBush1 1" from the free SpeedTree package. "YesBush2 1" has the same problem.
I like how these bushes look close up, but at lower LODs they start to flicker very badly whenever the camera is in motion, to the point it almost hurts to look at.
I think this has to do with the very small holes between leaves creating aliasing problems when viewed from a distance, but I tried increasing anti-aliasing to 4x in the quality settings and adding an anti-aliasing post-processing module to the main camera, with no noticeable improvement. I also tried playing with the LOD thresholds, but the only thing that helps is bringing the billboard way closer to the camera, which is alright for these distant hills but looks terrible for bushes closer to the course.
There are probably design-level things I can do to mitigate or mask this effect, but I really like the look I'm getting aside from the flickering, so just hoping someone has a technical solution to this.