Clip object affects objects with non-full opacity when blend mode is used

[James W]

When using a clip group in a layer that has the layer blend effect not set to "normal" the layer blend effect will get applied to the area outside of the clipped object but inside it's bounding box. Attached SVG demonstrates bug. The horizontal line though the stars is a result of clipping the yellow object with a solid black box. Changing the black box to have no fill does not remove the artifacts, neither does setting its fill opacity to 0.

Steps to reproduce:
1. Create a layer with an object, set the objects fill opacity to 50%
2. Create another layer with two objects, set one to solid black and use it to clip the other object
3. Change the second layers blend mode to anything other than normal
4. Move the clipped object over the one in the lower layer