Distortions and Blurs posprocessing materials pack has been updated.
The update was done in Unreal Engine 4.7.4 (initial release was created in 4.6). It mostly targets incorrect material preview in the editor window related to the mismatch in the visible window size and render target size.
Version 1.1.0 change notes
-M_Bulge, M_Underwater, M_CircularBlur, M_RadialBlur, M_Distortion
Fixed uv coords in the custom nodes to properly display the effects in the editor windows.
-M_Distortion, M_GaussianBlur5x5Mask, M_GaussianBlur9x9Mask
Using ScreenAlignedUVs instead of TexCoord to sample texture maps.
Removed this texture. Now using BilinearTextureSampler0 in the custom nodes to sample render targets.