Flex6500 strange behavior!?

I received my trade up flex6500 last night.  This morning I was playing around with it and came across something I don't understand.

I had slices C & D on 20m watching both CW and the RTTY contest.

I had slices A & B down on 40.  In the upper panadapter I changed band to 15.  Looked around a bit but nothing really going on, then I changed to 10m.  Same thing.  A few rtty stations but not much.

When not operating I like to listen around and I always get a kick out of the CBers and how they talk to I took the top panadapter and began to drag it to the right until I was in some of the CB band.

At point point I heard a click in the radio and noticed everything going on, on 20m went kind of dead.  So I slide the top pan back and click they came back.

The attached movie shows this in progress:
https://dl.dropboxusercontent.com/u/7578983/Flex6500OddBehavior.mp4

Perhaps this is expected as I have the single SCU but I was little surprised to see it do this.  Is this to be expected?  IE if I want to use one pan to listen to stuff outside of ham bands that the other pan will kind of go deaf?