There was a longer investigation into this issue, covered thoroughly here:
Whilst this may not be the actual Pololu DRV8825, I suspect the same discussion would apply to the general case, i.e. have the same issue as the discussion shows, which results in what has been called the 'salmon scale effect' which is very regular bumps in the 3D print walls, which look like salmon scales on a curved surface.
I'm suggesting putting genuine Pololu DRV8825 in, might have the same problem, and so perhaps configuration advice could still apply, if any readers can assist, greatly appreciated. Seems silly that many Black Widow owners are changing to TMS2100. The change might be redundant, if we can figure out the cause. I think our drivers are set up in dual decay mode.
Any advice welcomed.