It's clearly not right. I'm disappointed with my cellular 128 GB mini Retina as well.
I had ordered it on November 21st, and waited forever for it to finally get here on December 8th. But when I booted it up for the first time, I see the yellow band at the bottom of the screen. It seems that you can add me to that long list of people with a defective iPad mini retina screen. The nearest Apple store from me is over 100 miles away. And after waiting for what seems like an eternity to get it, I think I'm going to have to try to live with that yellow band at the bottom of my screen.