I'm not clear about your issue: is it a) clipping should only be done after filters are applied (this is what I see in Inkscape), or b) blurring a clone should be clipped as if the clipped original was blurred and not the clone?
I'm not clear about your issue: is it
a) clipping should only be done after filters are applied (this is what I see in Inkscape), or
b) blurring a clone should be clipped as if the clipped original was blurred and not the clone?