When I relieve the pressure in my new system the gas has the ipa hop smell, is this going to then make my stout taste partially dry hopped if they are hooked up to the same manifold splitter?
What kind of splitter do you have. Most good manifolds that have a on/off valve also have a check valve in them.
I don't think mine has any check valves, otherwise if I let the relief valve on the manifold open it wouldn't smell hoppy would it?
I wouldn't think so. It's possible though.