This picture shows the bump in the pocket that is caused by what I am describing. And the Thingiverse link is here
A quick video shows what is going on with the brush and the Z axis carriage.
I have to have the brush. The vac attachment I’m using does a good, but not great job without one, so an update to the design is in the works.
I’m sharing this because it took a lot of time to figure out why this bump was happening and I hope to save others from the frustration.