Texture atlas Frac pixel artifacts

[Sitrec]

@;122040

You can get rid of the frac artifacts by manually computing the Mip level. There is a material function called CimputeMipLevel which provides the necessary math.
The downside is it will add ~15 instructions due to the log2 function and it removes anisotropic filtering (although Temporal AA helps to fight the aliasing/noise).

Here’s a simple material setup for 2 sub-textures of one atlas:

It worked pretty well, the artifacts are gone and there is hardly any noticeable bleeding now, only on hills far away.
I have a new problem though, in certain angles (it seems) the texture turns brown instead of the green it should be and there are some new lines appearing.

I’ve included a picture. Please ignore how horrible it looks.

Any idea what might be causing this?
Thanks in advance!

edit It seems like this is also some kind of bleeding as it matches the color of adjacent textures.