Is there any way to fix this seam? A healing brush of some sort? Or is it just something I'll have to do post-substance Ignore the crappyness, I am getting familiar with substance and just made it to practice :P
It's worth identifying what part of your substance is causing the seam. In your case, it looks like a noise generator. One way that is possible now is to make a sort of buffer/mask near your seams, and mask your noise with this buffer, so there is no contribution near the seams. This can work, but can also cause a weird…