Lines appearing in custom brush
I created a custom brush follwoing this tutorial https://www.youtube.com/watch?v=qvTNKSalhEw however when I try to use it, it's almost like there's an invisible grid in the document that shows up in the middle of my strokes. It doesn't matter where I start the brush stroke or the brush size, the lines are always in the same spot on the document. It also doesn't happen for the default brushes. I can't find anything when I try to google the problem. It seems to be a problem with the brush but I have no idea what. Any ideas what might be causing it and how can I fix it? 
