For test, i'm using simple brush with "predefined" brush tip, which is just filled square.
The preset is defined so that:
* rotation depends on drawing angle
* ratio depends on "fuzzy stroke".

I think that rotation should be applied after ratio; so, if you take a square, then apply "ratio" = 0.5, then rotate it, you will get a rotated rectangle. 
But if you first rotate the square, and next apply ratio, you will get a parallelogram. I think this is not what intended.

Will attach a screenshot.

Reproducible: Always


Actual Results:  
brush draws series of parallelograms.

Expected Results:  
brush draws series of rotated rectangles.