Noise with background set to alpha

I am experiencing a problem when setting the background color of a noise module to alpha by dragging down the A setting to 0. What seems to happen is that a very small perhaps 1 pixel width ring of the old background color still exists along the edges of the foreground noise color when contrast is very high. This can be made obvious if you choose something like a bright red as the background and set it's A to 0 and contrast to 100. The background color creeps through on the edges with every color, while it may not be very noticeable and sometimes might be desireable to have that little border - it does not play well with things like blur. Try leading the noise into a blur and you will see the ring really starts to show!

...

noise alpha blur problem.ffxml

this one shows that the problem exists even when the noise bg is set to white and 0 A.

noise alpha blur problem 2.ffxml