This issue is being tracked as a golden with AiksTest.CanRenderForegroundAdvancedBlendWithMaskBlur.

The applied blend should only be impacting colors of the shape modulated by the blurred mask. However, the blend affects pixels outside the blurred area. This isn't something that can be solved inside of the GPU blend filter itself -- this needs to be resolved during the geometry negotiation in Aiks, which actually handles applying both the mask blur and color filter.

For this case:

1. The color filter should be getting applied on the CPU.
2. The mask blur should be getting applied as a single Gaussian Blur over the rendered geometry.