Trying to compose a masked shape with a little blur effect.
Mask is a Linear Gradient Brush.
After selecting Blur as Effect on the shape, the masking stops getting applied.
This seems to affect any combination of Brushes with any Effect
It is very confusing depending on the order of creation, if ( in my case) Blur was set first, Opacity Mask seems completely non functional without notice.

Repro Path:
1.- Create a Rectangle
2.- Apply any opacity mask to it. A linear will do, make sure it has some part translucent
3.- Apply a Blur effect with Radius 0 to the same rectangle

Expected:
Both Blur and Mask can work together

Actual:
Mask stops working the moment Effect is selected.