Not seeing that with my SVR. If you aren't in dynamic or are running with the exhaust baffles closed in dynamic only one of the exhaust pipes on each side are active. I think it's the outside ones, but to be honest I haven't really looked underneath to be sure. If you tend to run that way a lot, then the outside ones would get darker than the inside just under normal operations. Since one side is darker, it might be worth getting things checked out. I think that may mean that a cylinder on that side may be running a bit rich. Maybe a sensor is off, but typically you would get a notification on that.
Here is my thought as shown below (understanding this may not be exactly what yours looks like) notice that the exhaust pipe from the engine back is directed primarily to the inner exhaust tip. In combination with what @PA-FPace-F has mentioned that my be your problem, Your are running rich on one bank and not the other and the sensor is not detecting it.
My Vette will many time have the inner tips show a little darker when the both exhaust valves are open (usually when I get on it a lot).
Funny you mentioned this, as I let mine idle for a few minutes to see if I could download a software update (none available for me), and when I gave up and walked around the car, I noticed only the 3rd exhaust pipe had condensation on it. I know the computers often run a warm-up mode to get the cats hot, but that wouldn't explain the asymmetrical valve configuration I observed.
Looking at MKenM's picture, I might want to correct what I said and say perhaps the inside pipes are the ones that are always used. Not sure though, really need to leave it running in normal and go back there and see which ones are active.