Brush creating unwanted lines.

[rosenh]

I created a brush, not too complicated.  I'm making sketchstrokes to create a sketchy background.

But it's doing a bizarre thing.  There are lines all across the page, as if there was something with texture underneath my drawing.  There lines are very even, aligned to the "paper" not to the brushstroke. Is there some paper setting I didn't know about??  What's going on here?

[rosenh]

I'm using the latest PSD CC.  I just updated it to make sure it wasn't a glitch.  

It looks like it's just this one brush?

I'm using an old Wacom.  I'm running Mohave on an ample iMac.