I do this. The rear cog is somewhere in the middle when I shift the front - but I am not talking about what happens when I shift the front (that is fine) the problem is when I shift the rear cog. Pretty much ANY shifting of the rear cog when I am in the middle chain causes all kinds of noises and catching and not-fun things to happen. Other two chains are fine when I shift the rear cog.

Sorry for any confusion.