Repro Steps:

1) Create a Page
2) Add any highres image under the root grid, and set its Stretch to 'Uniform to Fill' so that it fills the entire viewport.
3) Add a Pinch effect on the Root grid
4) Set the Pinch effect's properties to be: Amount: -1 | Center: 960 / 510 | Radius: 1080
These measurements should place the Pinch effect in the middle of the 1920x1080 Stage, and expand the effect from the very top, to the bottom of the Viewport.
5) Zoom in and out, and pan the Stage left and right.

Observe how the rendering of the effect changes depending on X/Y and Zoom positions

Expected Results: Effects are rendered consistently, independently of the Stage's zoom level/position within Studio.