The clay on the right has got those random borders on the edges, and it looks terrible. I have no issues editing JSON files if necessary, I just don't know what to change. The cyan on the left is textured concrete...nice and smooth with no black edges.
Any help, or a point in the right direction would be helpful.
Hopefully it’s not too late, but that’s happening because the block is set to randomly rotate the texture. To turn that off go to the “blocks.json”, scroll to the part relating to your block, and change the “isotropic” command from true to false.