Oddly enough I can’t import the material again. 
Same engine, same project, even a new project… nothing. Perhaps there’s something in the material (like a material function or something) that I don’t have which is preventing me from opening it? Just speculation.
Anyways, your “white lines” issue appears to be a simple blending issue. You can see how the lines disappear on steeper slopes here:
Image
This would indicate your Z axis is blending a lot with the X and Y axes (the steeper the slope, the less the Z axis blends). With a cliff texture like this (directional textures or where a top projection isn’t really desired) the best solution would be to not project on the Z axis entirely (by cranking up the “X-Y Projections Angle” and removing your Z Projection UVs/Z Projection Weight lerp where you sample your textures). This would eliminate the problem entirely.
But, if you need that Z projection, you should be able to tinker with raising the “X-Y Projections Angle” and lowering the “Projection Smoothness”. With directional textures like this one, the result will never be perfect, but you can probably find an acceptable middle-ground.
Now, for your seam issue… I honestly have no idea. 
The fact it only happens at that angle (which can be seen in the other pictures too) is really throwing me off, and without the ability to open the material, I really can’t help that much. I’d say start by looking over your projection weights, where you applied the dithering. Then, if there’s no issues there, trace it backwards, checking your 00 projection axes and 45 projection axes.
I’ll keep trying to open the material and I’ll let you know if I can.
As a final note, the macro-blending uses another 3 samples, so if Frenetic’s solution works for you, it would probably be better (performance wise). Not necessarily, but likely. That said, I’ve tried stochastic-sampling once, and I wasn’t happy with the results. It created a bunch of small seams which were visible when you got close (like a player walking on the ground). But, another grain of salt, it’s possible I followed a bad tutorial. I found a better solution for my case which was more performant and better quality (I did a simple fade to color, since the textures were stylized and lost detail quickly, I could replace it with a simple color).
In the spirit of learning, I’d say follow some tutorials for other anti-tiling methods. Worst case scenario, you learn a little more about materials. Best case scenario, you have a better anti-tiling method than macro-blending. IMHO, macro-blending has been around for a very long time… it’s probably time to upgrade.
Glad to hear it’s working.
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