NOTE: This bug effects only the Beat Tones shader brushes for Procreate downloaded between 18 March and 25 April 2019.
When you scale the brush tip of your Beat Tones shader brushes both then brush tip and the brush texture change scale. This makes it difficult to fill tight spaces with halftone texture using a small brush tip, whilst retaining a larger texture scale or vice versa.
Update to the latest version of the Beat Tones Brushes for Procreate here.
In the Brush palette, double-tap the affected brush brush, then go to the Grain tab and change the Zoom slider to 0.
The brush tip will now scale independently of the texture.