I’ve tried messing with the offset of the texture, but I can’t do this, as it’d ruin any even connection between grass and dirt. Every other block is the exact same and does not have this problem.
By exact same, I mean 3x3x3, with texture size of 3x3 and offset of 1.5x1.5
Have a look at your texture to make sure the green line isn’t on that image.
What colour is the block you have the Texture on?
Does the Texture have any Transparency to it?